Introduction

The 2017 Audi A8 and Audi S8 are the brand's largest luxury sedans. For 2017, the lineup has been simplified: All 2017 Audi A8 models ride on the long wheelbase, featuring greater back-seat space. The high-performance 2017 Audi S8, on the other hand, continues on the shorter wheelbase. 

Two engines are available for the 2017 A8, a V6 and a V8. (The costly, heavy W12 engine and the turbodiesel V6 are no longer available.) 2017 Audi A8s come standard with the sport package, with its more aggressive bodywork, front and rear. 

Built with a light but strong aluminum space frame, the refined A8 is a full-fledged contender against the biggest BMW and Mercedes-Benz sedans. Simple, sophisticated body contours help keep the A8 fresh as years roll by. 

Audi's base engine, a supercharged 3.0-liter V6, develops 333 horsepower and 325 pound-feet of torque. If the V6 won't quite suffice, the twin-turbo 4.0-liter V8 generates a brawnier 450 horsepower and 444 pound-feet. That's enough to propel the A8 to 60 mph in a breathless 4.4 seconds. Both engines mate with an 8-speed automatic transmission and Quattro all-wheel drive. A dynamic handling package now includes a rear sport differential. 

Numerous safety features include front knee and rear-side passenger airbags. Audi's Pre Sense system can tighten seatbelts before an impact occurs. Advanced safety technologies come in option groups, including adaptive cruise control with stop/go capability in traffic, blind-spot monitoring, lane-keeping assist, and Night Vision. Curiously, a rearview camera is optional, though parking sensors are standard. 

Stepping way up the performance ladder, Audi's S8 unleashes a 605-horsepower, twin-turbo 4.0-liter V8 that develops 517 pound-feet of torque. The exterior might be plain, but occupants enjoy deep Valcona bucket seats, along with a rousing road experience. An S8 is able to hit 60 mph in a startling 3.7 seconds. 

Only a few cues suggest the S8's potential: LED lighting, 21-inch wheels and quad oval tailpipes. Adaptive dampers and air springs help keep the S8 calm, when it's not being pushed hard. The S8's trunk is unusually small for a full-size sedan, and rear leg space is limited by the short wheelbase. 

Lineup

Two engines are available for the 2017 A8 L. 

A8 L 3.0T ($82,500) has the long wheelbase and includes the supercharged V6 engine, Quattro all-wheel drive, leather upholstery, navigation, full-LED headlights, power front and rear seats, a sunroof, and power-closing trunk lid. Standard infotainment boasts satellite radio, Bluetooth phone and streaming, Bose speakers, and a USB port. 

A8 L 4.0T ($91,500) features the twin-turbo 450-horsepower, 4.0-liter V8. 

S8 ($116,850), the super-performance edition, is built on a short wheelbase and comes with a 605-horsepower V8. (Prices are MSRP and do not include destination charge.). 

Walkaround

Befitting its elegant, sophisticated nature, the A8 relies on subdued styling, with nothing flashy or excessive. Among the group of executive-level luxury full-size sedans, in fact, Audi's A8 has one of the most restrained, low-keyed exteriors. 

Substantially less sleek and dramatic than the Audi A7 sedan, the big Audi A8 isn't short on detail work. Full-LED front lights and taillights, for example, highlight the expansive elegance of the sedan's hood, along with its shoulders. For 2017, the A8 body gets a touch of flair, courtesy of the newly standard sport appearance, with its hint of the super-performance S8. 

Interior

The Audi A8 cabin is plush and comfortable. Whether trimmed with leather, wood, aluminum, or plastic, the A8 interior seems to omit not a single thoughtful detail, augmented by use of excellent materials. 

At startup, for instance, tweeters rise from the dashboard, which is surrounded by splashes of chrome. The gearshift lever is patterned after a yacht's throttle control. 

Standard seats have 18-way power adjustment and are upholstered in lush perforated leather, softly padded atop a firm structure. Four adults benefit from abundant space, especially the pair in back, helped by multi-zone climate control. If power adjustment is included, the right-rear passenger has access to a footrest, whereas the left-hand occupant enjoys massaging functions and a reclining seat. Audi's standard infotainment system impresses, but some controls are duplicated needlessly. 

A dual-panel sunroof keeps the cabin bright, with no loss of head space. Trunk space is ample, at 13.2 cubic feet, with a long lid and wide opening. 

Serenely silent much of the time, the A8 keeps most wind and road noise from entering, though tire sounds might seep in while accelerating. Abundant leg space in the back seat helps make it possible for rear passengers to get work done in comfort. 

With Audi's Multi-Media Interface, a console knob permits scrolling and selecting audio, phone, climate, and navigation functions. Voice control doesn't always respond properly to commands. 

Driving Impression

Despite its weight, an A8 feels comparatively light and nimble, helped by its aluminum space frame. Quattro all-wheel drive provides sure-footed confidence, despite the suspension's complexity. The torque split can vary between 40/60 and 60/40 front/rear, as needed. 

Audi's 3.0-liter V6 responds well, courtesy of strong low-end torque. However, it's not especially smooth, and can become noisy when pushed hard. Acceleration to 60 mph takes 5.5 seconds, helped by well-spaced gearing in the transmission, which incorporates paddle shifters. Not only does the transmission shift smoothly, it seems to pick the best ratio without delay. 

The available 4.0-liter twin-turbocharged V8 is essentially the same engine used in the hot S8, but in a reduced state of tune. 

Drive Select can control powertrain responses, steering weight, and suspension operation. Picking Comfort, Auto, or Dynamic mode can alter the experience from sedate all the way to dramatic. In Comfort or Auto mode, the transmission tends to shift quite early. Yet, pushing the pedal forcefully yields repeated downshifts. An Individual mode may be customized, to provide highway behavior between those two levels. 

An A8 isn't particularly frugal, which won't surprise any typical buyer. With the V6 engine, the A8 L is EPA-rated at 19/29 mpg City/Highway, or 22 mpg Combined. Picking the V8 drops the city figure to 18 mpg. The S8 sedan is EPA-rated at 15/24 mpg City/Highway, or 18 mpg Combined. 

Summary

Packed with impressive detailing, Audi's A8 is one of the quietest, most comfortable, and spacious executive-luxury sedans on the market. Whether V6- or V8-powered, every A8 gets all-wheel drive, an 8-speed automatic, leather, and power amenities. For long highway journeys, the A8 is hard to beat ? and well-off shoppers who demand ultimate performance can gravitate over to that sizzling S8. 

Driving impressions by Aaron Cole, The Car Connection. James M. Flammang contributed to this report.