Big, powerful, smooth and luxurious.

Introduction

The Audi A8 is a big luxury sedan designed to challenge the BMW 7 Series and Mercedes-Benz S-Class. It beats them in some areas and in others it offers an individualistic alternative. In many respects, the Audi A8 raised the bar for performance. Several versions are available, the A8, the A8 L, the A8 L W12, and the S8. 

Three versions are available. The standard A8 boasts instant throttle response from its powerful 4.2-liter V8 and six-speed automatic transmission, while quattro all-wheel drive and an adaptable air suspension provide an excellent balance between handling and ride quality. The A8 offers a supreme sense of control with Gibraltar-like stability, benefits of its lightweight, Aluminum Space Frame that bonds the car into one cohesive unit. 

The cabin is elegant and comfortable, and tops the class in finish quality. Audi's Multi-Media Interface, or MMI, integrates controls for various features and electronic systems into a big knob. It's a little easier to learn than BMW's iDrive, but it isn't easy. There is a learning curve and sometimes we find ourselves having to work harder to perform simple functions and wonder whether this is progress or burdensome technology. 

The A8 L rides on a stretched wheelbase that provides more room and comfort for rear-seat passengers and uses the same engine as the A8. 

The A8 L W12 upgrades to a 12-cylinder engine and a whopping 450 horsepower. It's the only 12-cylinder sedan from Germany's big three luxury brands with all-wheel drive. 

The Audi S8 is powered by a 5.2-liter V10 and comes with a firmer suspension, faster steering, and bigger brakes. The S8 is distinguished by special trim and equipment inside and out. The S8 is perfect for triple digit speeds on wide-open highways and would be an excellent choice for a cross-country race. It's also a good selection for getting away from enemy agents, for those in that line of work, particularly in bad weather. For driving through the neighborhood or in stop-and-go traffic, however, we found it suffers from an overly sensitive throttle that makes smooth takeoffs a bit too challenging. 

For 2009, changes to the A8 are minimal and in the category of repackaging some features and options. 

Lineup

The 2008 Audi A8 is available in four variations: The A8 4.2 ($70,050); A8 L 4.2 ($77,900); A8 L W12 ($120,100); and the S8 5.2 ($96,200). All come with Audi quattro all-wheel drive. 

The A8 4.2 rides on a 115.9-inch wheelbase, while the A8 L adds 5.1 inches in both wheelbase and overall length. Both are powered by a 4.2-liter V8 rated at 350 horsepower and come with a six-speed automatic transmission with Tiptronic manual shift control. Both models come with dual-zone automatic climate control that uses temperature, moisture, and infrared sensors to demist the windows before they can even think about fogging. Other standard features include leather upholstery; heated front and rear seats; 16-way power adjustable front seats with lumbar adjustment; interior air filter; power tilt/telescoping leather-wrapped steering wheel with audio controls; cruise control; memory for the driver's seat, mirrors, and steering wheel; heated power mirrors with auto-dimming and passenger side tilt-down back-up aid; power windows and door locks; remote keyless entry; sunroof, Bose AM/FM radio with 6-disc CD changer; Sirius satellite radio; auxiliary audio input jack; navigation system with voice recognition; Bluetooth wireless cell phone link; trip computer; auto-dimming rearview mirror; Homelink universal garage door opener; rain-sensing wipers with heated nozzles; trunklid-closing assist; automatic bi-xenon adaptive headlights with washers; theft-deterrent system; front and rear fog lights; adjustable load-leveling air suspension; front and rear limited-slip differentials; and P255/45HR18 tires on alloy wheels. The A8 L adds manual rear side sunshades. The parking brake is operated by a switch. 

The A8 L W12 rides on the 121-inch wheelbase and is powered by the 450-hp W12 engine. It comes with ultra-luxury amenities, including front and rear park assist; power sunshades for the rear windows; power-adjustable rear seats; leather upholstery on the door panels, console and dashboard; rear dual-zone automatic climate control; massaging and ventilated front seats; Alcantara interior trim; wood and leather-wrapped steering wheel; rearview camera; keyless access and starting; door-closing assist; power trunklid; trunk pass-through with a ski sack; and P255/40HR19 tires. The A8 L W12 also comes standard with a full-length rear-seat center console, housing elaborate climate controls and seat adjustments, plus a dual-screen entertainment system; this limits seating capacity to four, though the rear center console can be deleted at no cost in favor of a three-place bench seat. 

The S8 rides on the standard 115.9-inch wheelbase, and features a high-performance 5.2-liter V10 rated at 450 hp. The air suspension is firmer, the brakes are larger and the steering is quicker. Extra bright trim and 20-inch wheels with P265/35R20 tires contribute to a distinctive look outside; while inside are sport seats upholstered in two-tone leather, darker wood or carbon fiber trim with aluminum accents, and white-on-gray italic gauge faces. 

Option packages for the A8 and A8 L include a Sport Package ($4,300) with firmer suspension settings, 20-inch wheels with P265/35R20 summer performance or all-season tires, and a multi-function leather-wrapped three-spoke steering wheel with shift paddles. A 14-speaker, 1000-watt Bang & Olufsen sound system custom-tailored to the Audi's interior acoustics ($6,300) is available. 

Options for the A8 and A8L include adaptive cruise control ($2,100), which uses radar to maintain a prescribed distance from traffic ahead; four-spoke wood and leather multifunction steering wheel with wood shift knob ($690); a solar-powered sunroof panel ($790) that blows cooling air through the car while it is parked (and replaces the standard glass sunroof); front seat massage and ventilation ($1,500); rear-seat electric lumbar adjustment ($350); 19-inch wheels with P255/40R19 all-season tires ($1,900); and, for the A8 L only, a personal refrigerator ($1,500) in the trunk accessible through the rear-seat armrest. 

A8 L W12 options are limited to the adaptive cruise control, solar roof panel, four-spoke multi-function steering wheel ($200), Bang & Olufsen stereo, refrigerator, full-leather upgrade ($3,900), and 20-inch wheels with P265/35R20 tires ($3,200). 

Most of the stand-alone luxury options offered on the standard-wheelbase A8 are available on the S8 for the same prices. Carbon-fiber interior trim ($550) is available. 

Safety features on all A8 models includes 10 air bags, including dual front airbags, front and rear side airbags, curtain side airbags, and front knee airbags. In a crash, computers quickly determine which dual-threshold, dual-stage air bags to deploy, how quickly to deploy them, and how intensely they should be deployed. Also standard are antilock 4-wheel disc brakes with brake assist, traction control, electronic stability control, front-seat active head restraints, and a tire-pressure monitor. A Technology Package ($3,600) adds Audi Side Assist and Audi Lane Assist. 

Walkaround

Elegant. That's how we'd describe the A8 in a word, but elegant in a forceful fashion that's not at all prissy. The A8's distinct wedge shape features a short front overhang, a low hood-line and a high, powerful tail. The shoulder line rises to the rear, creating the impression of a crouched beast ready to spring. The A8 is expressive in an understated Audi way, and people will know you mean business when you fill their mirrors. 

A8 L models are 5.1 inches longer than the standard A8 and S8. (L stands for long-wheelbase.) Inside the car, those 5.1 inches translate entirely into increased rear-seat legroom. Choose the A8 over the A8 L if squeezing into tight parking spots is more important than a vast rear seating area, remembering that the standard A8's rear accommodations are quite expansive by typical sedan standards. 

At 115.9 inches, the standard A8 is fractionally longer in wheelbase than a Cadillac DTS. The A8 L is essentially the same length overall as a Mercedes S-Class and BMW 750i. The A8 L wheelbase stretches 121.0 inches, which leaves it 3.6 inches short of the long-wheelbase Mercedes and 2.2 inches short of the long-wheelbase BMW. Other things being equal, a longer wheelbase offers more passenger room and increased stability at speed, but is less maneuverable on canyon roads and in tight parking lots. The Audi is an inch wider than the Mercedes-Benz and comparable to the BMW. 

All the doors open extra wide, making it easy to get in and out. The flush, lever-style outside handles are attractive, but we find them harder to use than the type you can put your hand through, such as those on a Mercedes. 

Standard on A8 4.2s are 10-spoke 18-inch alloy wheels with 255/45HR18 all-season tires; these provide excellent handling and ride comfort and superb grip in the wet. The optional 19- and 20-inch wheels and tires more aggressively fill the wheelwells and provide a surprisingly smooth ride in spite of their short sidewalls. The A8 L W12 gets the 19-inch wheel/tire package standard; with 20-inch wheels available and 18-inchers (which offer the best ride) offered as a no-cost option. 

All models feature a tall, vertical grille that connects Audi's familiar horizontally split grilles over the front bumper, emphasized with a chrome surround. 

The rear of the A8 models feature taillights that fit flush with the clean rear design. Turn signals use LED technology and feature side repeater lamps to signal your intentions to drivers alongside. Dual exhausts poke from below the beautifully integrated rear bumper. 

The S8 has a bolder front end, with a bright finish emphasizing the vertical elements of the family grille, and a honeycomb texture for the air intakes on either side of it. A red-and-black S8 badge is offset to the lower right. Sharp-eyed Audi-watchers might notice additional S8 badges on the front fenders and front brake calipers, as well as a V10 badge on each front fender and unique aluminum-look trim on the side mirrors and door handles. Subtle, too, are the S8's integrated deck-lid spoiler and light-reflecting panel in its rear apron; not so subtle are its four oval exhaust tips. 

The aluminum space frame saves about 300 pounds compared to a conventional steel frame, allowing more features without overburdening the car with weight. An A8 L 4.2 weighs 150 pounds less than a BMW 750Li and only 23 pounds more than a Mercedes-Benz S550, neither of which have all-wheel drive. The A8 benefits from a highly rigid structure, which means less flex, and the A8 feels as if it's milled from a single block of bar-stock aluminum. A rigid structure is the key to a smooth ride quality and sharp handling. 

Interior

The Audi A8 comes loaded with features, and each model is comfortable and luxurious. Interior design is clean and classic. A choice of leathers and wood trims ensures a touch of individuality. Handsome Valcona leather seat upholstery comes standard, with attractive Alcantara (suede-like) door inserts. Walnut, sycamore, and birch are the standard woods used to warm the interior. A swath of aluminum around the dash and doors brightens the interior. The mix of wood and metal is pleasing and adds a sporting flair. In total, the A8 cabin is handsome and remarkably rich in appearance. Audi is known for high-quality, well-designed interiors and the A8 lives up to that reputation. It looks and feels like a special place to be. 

The A8 seats are supportive and comfortable and adjust 16 ways. A memory feature keeps all the settings for four different drivers (or moods), including climate controls. Front and rear seats can be heated and ventilated. The center console provides generous storage, and the electroluminescent instrument panel adjusts brightness automatically according to ambient light. The four-spoke, leather-covered steering wheel has a hub fashioned to replicate the shape of the grille. 

In the A8 L W12, virtually every surface that isn't carpeted is covered with leather, save the top of the dash and headliner, which is made of Alcantara. Order the Leather Appointment Upgrade and the dash gets covered in leather, too, as well as the whole of the inner door panels, instead of just an insert. The double stitching on the seats in contrasting colors is really wonderful. 

The S8 gets special seats upholstered in two-tone Valcona leather with contrasting stitching; or in all black if that's what you prefer. The wood trim in the S8 is an almost-black Gray Vavona, which contrasts more sharply with the aluminum-look highlights. Carbon fiber trim is optional. Instruments are white-on-gray with italic figures. 

A seven-inch color screen in the top-center of the dash of all models displays Audi's Multi-Media Interface, or MMI. Four buttons and a dial on the center console do the adjusting. This system is designed to consolidate interior functions into one control center, giving the driver lots of options without filling the dash with buttons. Audi's MMI features a shallower menu structure than BMW's iDrive, meaning you don't have to burrow as deeply through a maze of menus to get to the adjustment you want. Audi did not incorporate the climate controls into this system, and that's a good thing. Heating and air conditioning have traditional controls mounted high on the center stack, so you don't have to call up a menu to change the fan speed. You simply twist a dial. Occasionally, we twisted this when we really wanted to turn down the radio, but we learned. The MMI screen matches the look of the controls, and a Return button takes you back to where you were, like the Back button on a Web browser. 

Virtually everyone we've spoken to, from auto reviewers to consumers, rates Audi's MMI better than BMW's iDrive. But some rate the Audi system only minutely better, and don't like it much at all. Most have found Jaguar's elegant and traditional controls to be the easiest of all. The point? Designing controls to manage the ever-increasing number of performance, entertainment and communications systems in luxury cars traveling at high speeds remains a young, inexact science. Audi's system takes some time to learn and, at times, we found the technology overwhelming and distracting. 

Beyond finish quality, attention to detail is one of Audi's greatest assets. A secondary heater in the A8 is designed to heat up the rear cabin quickly. Ambient lighting in the interior allows control of mood in the cabin. Mood lighting is good. One small demerit is the power door that hides the MMI when the car is shut off closes in a jerky fashion. 

The A8 is quiet underway. The cabin is well insulated (the W12 features double-pane side glass), and conversation is easy at any speed, even in the nosiest ambient conditions. There's no wind noise in this car and the ventilation system was acoustically tuned to make the climate control as quiet as possible, even when the fan is at full blast. 

The standard audio system uses Bose noise compensation technology just like those fancy headphones you see people wearing on an airplane. It works terrifically well. Essentially, a microphone samples the sound and sends out sound waves to cancel out undesirable noise. The 12-speaker stereo sounds fantastic, with crisp bass and clear highs. An equalizer matched to the car's equipment and trim specification takes into account changes to interior acoustics caused by the choice of upholstery. A four-way diversity antenna aids AM/FM reception, and a list of all radio stations that can be received in a given region appears at the touch of an MMI button, though we frequently turned it the wrong way. The six-disc CD changer is in the glove box, and we found this inconvenient; ejecting a CD was a chore that distracted our attention from the road. We'd prefer a single in-dash CD player to this. Sirius satellite radio is standard, offering cross-country access to CNN, ESPN and other news and entertainment programming. Turn the system on and the silk-dome tweeters automatically extend from the instrument panel into their ideal positions. Expect people to ask what they do. 

OnStar telematics comes standard, offering operators who can give directions around the clock and provide myriad other types of information and services. Those operators will send help to your location should an airbag deploy. They can pinpoint the location of the car if it's stolen or unlock the doors remotely if you've locked the keys inside. 

The rear seats in the A8 are designed to be comfortable for the 85th percentile in height, and even tall passengers aren't likely to complain. Rear passengers have lots of controls available to them, including optional power lumbar support and optional rear-seat dual climate control. There's also a fold-down center armrest with a pass-through to the trunk. 

The A8 L's rear seats are much more spacious, with acres of legroom. In the A8 L W12, a full console with more elaborate climate and seat-adjustment switches splits the rear seats. A rear-seat entertainment system with dual screens in the back of the front headrests comes standard in the W12, and it also includes a six-DVD changer, remote control, one set of headphones, and two AV and two headphone jacks in the center console. This rear console eliminates space for one passenger, but it pumps up the club-room ambience. (A three-place bench can be specified instead.) The A8 L falls short of the long-wheelbase 7 Series in rear-seat head and leg room, but not by much. The A8 L rear doors are long, allowing easy access to the rear seat. 

The trunk is big and deep. The trunk is the same size on the A8 and A8 L. At 14.6 cubic feet it is significantly smaller than the cavernous luggage compartments of the BMW 7 Series (18.0 cubic feet) and Mercedes-Benz S-Class (19.7). Still, the Audi provides sufficient room for at least two tournament-grade golf bags or a couple of weeks' worth of groceries. The trunk houses a full-size spare tire. 

We found the coat hooks inadequate for picking up a big load of dry cleaning, however. 

The effort of operating an A8 is reduced by technology. An available Soft Close feature automatically sucks the side doors shut from a partially latched position. Audi's optional Advanced Key eliminates the labor of turning the ignition key or even having to pull it out of your pocket, briefcase or purse, allowing the doors to be opened and the A8 to start with a button as long as the coded key fob is within a certain proximity. We're not sure intelligent keys are a feature we have to have and often find them more trouble than they are worth. However, our car had the standard key and we had trouble finding the ignition switch one night as it was not illuminated. 

Driving Impression

In the Audi A8, a driver can use the Driver Information Display to set the optional Adaptive Cruise Control, which minds tailgating and maintains a safe, pre-determined distance to the car ahead. The Electronic Stabilization Program can help control the car when the driver can't. Electronic Brake-force Distribution keeps the car balanced in a panic stop, and Brake Assist slams the binders harder if the driver doesn't press as hard he or she should. Adaptive Air Suspension keeps the ride smooth and tires planted no matter the surface. There are moisture-sensing wipers, high-intensity headlamps and ten airbags. Yet all these advanced systems, identified by a confusing array of acronyms, don't mask one crucial point. The A8 can be a complete joy to drive, reminding all but the sensory deprived how pleasant gobbling miles in a big, fast luxury sedan can be. 

The first impression at the wheel of an A8 is its smoothness. There's nothing remotely resembling a squeak or rattle, and almost no vibration in the cabin. 

The 4.2-liter V8 delivers powerful acceleration, but its power delivery is sophisticated, not crude. The V8 responds with a muted roar to every poke at the gas pedal. No matter how fast the A8 4.2 is already going, the driver can tap into a deep well of acceleration-producing torque. Audi claims the 350-hp A8 4.2 can sprint from 0 to 60 mph in just 5.9 seconds. A sub-six-second 0-60 is quick. Top speed is electronically governed at 130 mph. In short, the A8 is fast traffic. The base engine is also the easiest on gas, with EPA fuel economy numbers of 16 mpg City and 23 mpg Highway. Those numbers aren't bad for a big, V8-powered luxury car, and they're bested only by the base engine in the Jaguar XJ. 

The 6.0-liter W12, rated at 450 horsepower, is quite remarkable. The A8 L W12 is a blast to gas. Throttle response is immediate, and the 12-cylinder engine delivers acceleration-producing torque in a wide, flexible power band befitting a luxury carmaker's flagship sedan. The W12 pulls hard up to its 6200-rpm power peak, and it feels like there's still more power coming when it hits the rev limiter. Moreover, the revs translate to executive-class thrust. Audi reports a 0-60 mph time of 5.0 seconds, very quick, indeed, with top speed governed at 130. The W12 is remarkably refined, docile, and tractable, particularly given 450 horsepower, but it does have a hint of an overly sensitive throttle so you might have to recalibrate your foot to avoid lurching from a standstill. 

The six-speed automatic that comes with either engine shifts up or down according to the driver's wishes, deftly sensing how quickly and how hard the throttle is mashed. The transmission features what Audi calls DSP (for Dynamic Shift Program), a form of smart software that selects from over 200 possible shifting programs to adjust to any individual's driving style. Upshifts are silky smooth in full automatic mode; in some instances, downshifts could come quicker, but the reserve of torque in either engine more than compensates for any shift lag. The automatic features Porsche's Tiptronic system, allowing the driver to slide it into a manually controlled mode and use either the shifter or available steering wheel paddles to choose gears. Manual shifting is never necessary, because the transmission is quite responsive in the automatic mode, but it can be fun. Here, however, we lodge a small complaint. Even in manual mode, the transmission will shift up at high rpm, rather than holding the selected gear, which seems to defeat the purpose of giving the driver manual control, but it's a good thing if you forget to shift. If you want an even sportier shift program but don't want to select the gears yourself, you can put the gearshift in S. This mode holds gears longer and downshifts quicker to keep power more readily on tap. It also hurts fuel economy, so use it sparingly. 

The quattro all-wheel-drive system offers excellent traction in slippery conditions, but also improves stability when cornering, whether under full-throttle acceleration or when the driver lifts off the gas suddenly in the middle of a turn. Quattro also eliminates torque steer, that pulling sensation on the steering wheel that powerful front-drive cars often exhibit under acceleration. 

An adaptive air suspension is used at all four corners on the A8, and it's a lot more sophisticated than the rear air shocks that could be inflated on 1970-vintage American station wagons. Four settings are available, selected electronically with the MMI. There are genuine differences in ride and handling with the basic Comfort and Dynamic settings, but neither is uncomfortably firm nor disappointingly mushy. 

In the Comfort mode, the A8 rides at the normal ride height (120 millimeters or 4.7 inches). Comfort might suggest a cushy, mushy ride, but that's not the case. Even on a narrow, undulating Kentucky backcountry road, we found the suspension well controlled with Comfort selected, yet still smooth, compliant and comfortable. Switching to the Dynamic mode lowers the suspension by 20 mm (about three-quarters of an inch). You might think Dynamic is buckboard firm, but we found it quite comfortable and compliant, though tuned for sporty handling and more aggressive driving. Both modes operate at all speeds, or you can switch to the Automatic mode. Here the system tailors the suspension damping to conditions and the way you're driving, automatically lowering the car at 75 mph. This is usually the best setting, as the system continuously matches the ride and handling to the situation, and does a good job of it. The ride is smooth and supple, without the slightest sensation of floating or wallowing. Lastly, there is the Lift mode, which raises the suspension 25 mm (about an inch) above the normal ride height. Lift is a good setting for gravel roads, snow, a nasty driveway or an abrupt transition, any situation that calls for a raised ride height. Exceed 62 mph in Lift mode and the suspension automatically lowers to the normal ride height. 

Despite its length and substantial weight, the A8 is impressively agile, and bears up well under aggressive driving. The steering is sharp and precise, providing excellent communication between the tires and the driver. One key to this big sedan's excellent handling and ride quality is its rigid aluminum space frame. The frame resists flexing and lets the suspension do all the work, which is how it's supposed to be. That's why the A8 delivers such a nice balance of fine handling and ride comfort. Driven to the limit in a corner, it understeers a bit, tending to push toward the outside edge of the pavement. To counter this, the driver simply lifts a little from the throttle, and the front tucks in and tracks through the turn. It works beautifully. 

Turn the wheel sharply at night and cornering lights automatically come on to illuminate the inside of the corner, a nice feature. 

The brakes are easy to modulate for smooth stops, and powerful enough for repeated hard braking from high speeds without fading. Of course, the A8 has every imaginable braking feature, including Electronic Brake-force Distribution, Brake Assist and ABS. The A8 exhibits very little nose-dive during braking and absolutely no drama in the hardest stops. It simply stops straight and true, allowing the driver to maintain steering control in virtually all circumstances. In an emergency situation, just remember to stand on the brakes, don't relieve pedal pressure, and look and steer where you want to go. 

The front and rear differential locks help assure stability even while turning under hard acceleration. An electronic stability program (ESP) compares vehicle behavior against driver input, and uses the antilock brakes and traction control to correct a skid or slide. Add quattro all-wheel drive, and the A8 will do everything physically possible to keep you heading where you want to go. 

Audi Side Assist uses radar technology to scan the area next to and behind the car. If a vehicle occupies that space or is moving up rapidly, the system turns on yellow lights in the side mirrors to warn the driver. If the driver puts on his signal and a vehicle occupies that space, the lights flash. We found Audi Side Assist worked as advertised and, while subtle, the lights were visible even in bright sunlight. 

Audi Lane Assist uses a camera mounted above the rearview mirror to monitor the road ahead. If the system detects that the vehicle is traveling above 40 mph and crosses a lane line without the use of a turn signal, it vibrates the steering wheel to warn the driver. The system can be set to three levels of sensitivity, one that triggers the warning when the vehicle is about to cross the lane line, one when the vehicle actually crosses the line, and one adaptive mode. We liked Audi's approach to this system. Other systems sound a warning that can become annoying because, in normal driving, lane lines are crossed on a regular basis, especially in curves. The vibrating steering wheel isn't as distracting, and the system can be shut off. In the most sensitive mode, however, we got false readings when the pavement changed, such as over bridges on the freeway. 

The S8 packs a 40-valve V10 with 450 horsepower, the same output as the W12 but at a higher 7000 rpm. The S8 boasts 398 pound-feet of torque at 3500 rpm vs. the W12's 428 pound-feet at 4000-4700 rpm. Digest those numbers a minute and you'll see that the V10 is really the performance powerhouse in the A8 series, playing the rogue racer against the W12's executive express. The shorter wheelbase and 10-cylinder engine save weight, improving acceleration performance: Audi claims 0-60 mph in just 4.9 seconds, with top speed electronically limited to 155 mph. EPA estimated fuel consumption is the same as for the W12: 13/19 mpg City/Highway. 

The S8 runs with the same six-speed automatic transmission as the A8 and A8 L W12, but it's programmed for more aggressive action. Paddle shifters on the steering wheel promise full manual control. The final drive ratio in the S8 is significantly shorter than in the other models (about 4.0:1 for the S8, vs. 3.3:1 for other A8s), for snappier acceleration in higher gears. 

The S8's air suspension is adapted from the A8 Sport Package, but the bushings, shock absorbers and air springs are firmer, to reduce roll and pitch. Steering is variable-ratio as in the A8, but geared about 10 percent faster around the straight-ahead position. Ride height is the same as with the Sport suspension, reaching a minimum of 3.7 inches at freeway speeds. Brakes are vented discs, 15.2 inches in front and 13.2 inches in the rear; standard tires are 265/35 on 20-inch wheels. The Bosch 5.7 electronic stability control on the S8 is programmed to interfere later and more briefly, leaving more control in the hands of the driver. It also keeps the disc brakes dry by lightly applying them, just enough to generate heat but not enough for the driver to notice. 

With all these modifications, it's no surprise that the S8 has sharper moves than the other models. Steering is quick and precise, and the sportier suspension bites better around turns. Still, this is a big car and the S8 is prone to understeer just like the other models. The S8's 20-inch wheels make the ride firmer, but not harsh. Even with the suspension in Sport mode, the S8 was comfortable on pockmarked Chicago streets. Discerning luxury buyers may find the ride too hard on occasion, but those with a sportier driving style will appreciate the S8's enhanced athleticism. Some of our test drivers find throttle response to be too sensitive, causing the car to lurch, but others felt it was just fine. 

Summary

The Audi A8 is fast, roomy, luxurious and exceptionally comfortable. It rides like a luxury car, yet it's taut and handles like a sports sedan. Loaded with innovation, the A8 is a thinking person's luxury car, more progressive, less traditional than a BMW or Mercedes. It's elegant but not arrogant, indulgent without being excessive. It's priced a little lower than comparable sedans from BMW and Mercedes-Benz, yet gives up almost nothing to either. Do you want a V8, V10, or W12? In Germany, where the autobahn beckons with no speed limit, that would be an easier choice, assuming money is no object. In our land, the advantage of the W12 or the sporty S8 is more image than reality. The price premium for the W12 seems like a lot for image, but it is a wonderful 12-cylinder sedan with all-wheel drive and we think it's a good choice. The S8 is a mixed bag. Some will like its sportier moves, but others will be annoyed by the firmer ride and sometimes sensitive throttle. 

NewCarTestDrive.com editors Mitch McCullough and J.P. Vettraino contributed to this report. Correspondent Kirk Bell contributed from Chicago. 

Model Lineup

Audi A8 4.2 ($70,050); A8 L 4.2 ($77,900); S8 5.2 ($96,200); A8 L W12 ($120,100). 

Assembled In

Ingolstadt, Germany. 

Options As Tested

Bang & Olufsen Advanced Sound System ($6,300); Leather Appointment Upgrade ($4,900); Technology Package ($3,500) with Audi Side Assist and Audi Lane Assist; Carbon Fiber trim ($500).