Sacrilege or sacrosanct? Blasphemy or brilliance? The reality of a four-door Porsche begs the question. Several, actually.

Perhaps the best interrogative is whether the 2010 Porsche Panamera deserves being classified as a genuine sports car, regardless of its nameplate and associated marketing hype. Hurtling at a serene 140 mph up the front straightaway at the legendary Road America racetrack begins to answer that question. But there's more to this inquiry than whether the latest model from Weissach is fast.

Expand or Die
Another obvious query seeks to understand why Porsche would want to offer a sedan in the first place. The answer requires a bit of history.

Few businesses thrive and retain their independence by remaining small. Porsche realized this as early as the 1960s, and has continually worked to expand their product range over the decades. Mixed results came along with products like the inexpensive 914 and 924 models.

These helped Porsche understand that less expensive cars were not the way to grow long-term and profitable market share. Today, in addition to the venerable and pricey rear-engine 911 models that define Porsche for many enthusiasts, the company offers the mid-engine Boxter and Cayman as well as the successful Cayenne SUV. The least expensive Porsche starts at $45,000.

While an element of the Porsche faithful regard the Cayenne as heretical (a sports car company should not build "trucks"), history has proven it to be a successful business decision. Recent 2009 sales data shows that the Cayenne accounts for over one-third of the company's U.S. sales, and ranks as Porsche's best-selling vehicle in this country.

One reason for the Cayenne's success is that in aggregate, more buyers want SUVs than sports cars. This same thinking pointed Porsche product planners toward sedans. Measured by volume, the sedan market is the biggest in the world, thereby giving Porsche its largest opportunity for growth ever.

The Porsche of Sport Sedans
When Mercedes-Benz, BMW, and Audi introduce new sport sedans, these ber models are always derivative of high-volume, mainstream four-doors. For example, the Mercedes-Benz S-Class full-size sedan targets practical European buyers with efficient six-cylinder diesel and gasoline engines. To satisfy M-B shoppers looking for more excitement, the same S-Class body and chassis can also be fitted with fire-breathing V-8 and V-12 engines producing as much as 604 horsepower--three times the entry-level models.

Of course, high-performance M-B models receive modifications compared to their high-volume stable mates, but differences are limited because high costs limit wholesale changes.

Because the Panamera is the only sedan Porsche builds, the company presents it as a no compromise vehicle, and their approach immediately reveals itself in the simplest ways. Normally, a vehicle's width, height, or length reflect little more than its overall size. With the Panamera, dimensions expose a performance-oriented engineering foundation. With a width and height of 76- and 55.8-inches, the Panamera is significantly wider and lower than, for example, the Mercedes-Benz S-Class.

Additionally, the Porsche's length is nearly 11-inches shorter than the big Benz. These squat proportions give the Panamera a lower and more stable stance than rival high-performance sedans, providing an excellent starting point from which to build a dynamic handling machine.

Interior packaging—how the car's body fits around its occupants—also helped dictate the Panamera's footprint. Its unique exterior dimensions afford ample room for four. Make no mistake, the Panamera is not a 2+2 with limited room in the rear. This Porsche offers four adult-sized seats inside the luxurious and purposeful space, and those buckets in the rear rank among the most comfortable chairs on the planet. A long wheelbase of 114.9-inches helped engineers stretch out the distance between the front and rear seats, giving those in the rear surprising room.

Headroom for all seats measures at 38-inches or greater, which is slightly more generous than the front headroom in the roomy S-Class. Pointing to the Panamera's sports car DNA, its driver's seat positions the pilot identically to the driver in a Porsche 911 in terms of height and placement. 

To ensure all occupants can get comfortable, front seats feature 18 adjustments, while the rear feature eight. A useful feature for those riding behind the front passenger is what Porsche calls the "Boss Button." Provided the front passenger concurs, the rear-seat passenger can control the front seat's position to create even more space aft.

The World's Most Expensive Hatchback
Having provided ample space for occupants, Porsche also needed the Panamera to be practical in terms of cargo capacity. The rear hatch opens to reveal 15.7 cubic feet of cargo room. While not cavernous, it is sufficient to store several golf bags or a week's worth of get-away luggage. Certainly marketers from Weissach bristle at categorizing the Panamera as The World's Most Expensive Hatchback, but with a base price for the Panamera Turbo model starting at  $132,600, it is.

A Front-Engine Porsche
While the Panamera's resembles the iconic 911 in many ways, engine placement isn't one. This sedan is Porsche's first front engine/rear-drive in car in over a decade. The U.S. market only gets V-8 and V-8 twin-turbo engines for now, while other markets also get a V-6.

Built alongside the Cayenne, the Panamera shares engines with the SUV, although the units destined for sedans get a handful of specific parts and unique tuning calibrations. Displacing 4.8-liters, the naturally-aspirated V-8 produces a smooth 400 horsepower while the turbocharged V-8 delivers 25-percent more. Both engines utilize direct fuel injection, a fuel-saving way to put minimal fuel into a combustion chamber while producing maximum power and reduced emissions. Extra fuel savings come from the engine's Auto Stop feature that can shut down the engine while the car is at rest at traffic lights, train crossings, etc.

Porsche offers only one gearbox in Panameras headed for the U.S., their PDK double-clutch transmission (Porsche-Doppelkupplungsgetriebe). While Porsche has used this technology for two decades in racecars, this is the first high-volume installation of the gearbox.

Even though the seven-speed transmission features two clutches, you won't find a clutch pedal in the driver's foot well. All clutch-work is done inside the gearbox automatically and faster than even the quickest race driver could manage.

Compared to a traditional automatic transmissions or Porsche's own Tiptronic S, the PDK' unique interal design requires less energy to operate. Additionally, having five closely spaced gears helps keep the engine operating in its most efficient range when accelerating around town. Lastly, the PDK's top two gears are overdrive ratios, 0.88 and an ultra-tall 0.59:1. These high ratios help keep engines speed lower at interstate speeds, another dynamic contribution to fuel economy. The base V-8 hits 16 mpg city, 24 mpg highway. The 500-horsepower twin-turbo V-8 drops only one mpg in each category. Economy is good enough that the Feds don't stigmatize the Panamera with a Gas Guzzler tax.

While these mileage figures don't equal of a Toyota Prius, not even a Prius dropped out of a cargo plane could match the slowest Panamera's top speed of 175 mph.

Fitted with different combinations of the above hardware, Panamera models break down as follows; Panamera S with the 4.8-liter V-8 and rear-wheel drive, Panamera 4S with the same engine and full-time all-wheel drive, and the mighty Panamera Turbo available only with all-wheel drive.

Does It Drive Like A Porsche?
The slowest Panamera, the "S," runs 0-60 mph in just 5.2 seconds and hits 100 mph in just under 12 clicks. This sedan can hustle. The Panamera's low-slung body and high-performance suspension hunkers down to rip through corners as if it were magnetized to the pavement. There is no question that the Panamera is a four-door, four-seat sports car.

But whether the Panamera drives like a Porsche depends on what Porsche model defines your frame of reference. For this author, it's the mid-1980s Porsche 911, a light-weight, muscular car with exciting dynamics and plenty of quirks.

The rear-wheel-drive Panamera S with the Sports Chrono Package behaves most like my memories think a Porsche should. It is the lightest of all Panamera models at 3968 pounds, and with its 400 horsepower running to the rear wheels, it's a lively drive. Diving deep into a corner, the steering communicates when the front tires are loading up with turning and braking loads. Laying into the throttle and unwinding the steering wheel when exiting shifts the weight back as the rear tires bite and work to put the power down, rocketing the car forward.

On the race track, with the Porsche Active Suspension Management (PASM) set on Sport Plus, engaged, the suspension stiffens and the PDK delivers near instant shifts at just the right place on the track, as if a Le Mans driver were remotely selecting the shift points. Stability at speeds exceeding 140 mph elicits a kind of calm that defies reason.

Moving into the Panamera 4S dulls driving dynamics ever so slightly, but adds a level of handling security that many drivers will appreciate. The AWD's added grip gives the car a forgiving, comfortable on-track persona.

Sliding into the Panamera Turbo Sport Chrono model amps up the experience—500 horsepower and a heady 568 lb.ft. torque will do that. With two small blowers spooling up early in the rev range, power comes on fluidly in a never-ending rush. The extra power masks the added weight of the AWD. The variable torque split that Porsche designed into the system and Porsche Dynamic Chassis Control help the Turbo feel more like a rear-wheel-drive sports car, so the Panamera Turbo carves through corners effortlessly and naturally with none of the push (understeer) often associated with AWD vehicles.

As good as the Panamera is as a sports car, it doesn't feel much like the aforementioned 80's vintage Porsche 911 a car that would spin in the middle corner if the driver blinked at the wrong time. Perhaps that's a good thing?

On the road with the PASM set to Comfort, all Panamera models deliver a smooth, controlled ride that those who want a sports sedan should enjoy. It's certainly not Lexus-like, but if that's what someone is looking for, they shouldn't be considering a Porsche. Our only complaint is that the PDK isn't as smooth in city driving as a conventional automatic transmission. Porsche recognizes this reality, and believes that Panamera drivers will overlook this characteristic because the PDK gearbox provides so many other dynamic benefits.

Looks That Grow On You
Porsche's classic 911 is recognized as an automotive design icon. The company's sleek Cayman model is universally recognized as a beautiful car. Unfortunately, honest eyes aren't likely to see unadulterated beauty when looking at the Panamera. The 911-esque front end is overly plain and the roofline looks like what it is; a stretched rendition of a 911's greenhouse.

The derivative look lacks the beauty of a Maserati Quatraporte or Mercedes CLS, but this is not to label the Panamera as ugly. The longer you're around the car, the better its looksor the less you care because everything else is so good.

Styling woes are confined to the sheet metal, because inside, Porsche created a beautiful environment. Soft leathers and impressive use of polished metals come across as elegant and utterly functional. Porsche also refused to cave in to the trend of providing a convoluted interface device (such as BMW's I-Drive). Porsche stayed with a phalanx of well-organized buttons, switches, and knobs that are easily navigated and understood.

Porsche's Expanded Range
So now Porsche builds a sports sedan to complement their traditional line of sports cars. Purists won't be happy, but those who truly appreciate Porsche should rejoice. Non-traditional models like the Panamera and Cayenne help keep the company healthy so that it can continue to engineer future performance machines those same purist will one day covet.

As for whether the Panamera is a genuine Porsche, this author believes it to be. Its "Porscheness" comes from how engineers approached the sedan's execution. Like the 911, it's a unique solution that works as intended.

Read More At AOL Autos:

- Man Drives With a Monkey Mask To Avoid Speeding Fines
- Why Ford's Winning By Not Taking Government Money
- Search and Read Stories at AOL Autos

Autoblog accepts vehicle loans from auto manufacturers with a tank of gas and sometimes insurance for the purpose of evaluation and editorial content. Like most of the auto news industry, we also sometimes accept travel, lodging and event access for vehicle drive and news coverage opportunities. Our opinions and criticism remain our own — we do not accept sponsored editorial.

Share This Photo X