ELKHART LAKE, WI – The results of the DNA test are in: It’s a Porsche.

A couple of laps around the 4-mile (6.4-km) Road America race track here and you have to wonder if there aren’t a few genetics specialists rubbing elbows with the automotive engineers in Weissach, Germany.

Despite the four seats and plenty of headroom, the all-new Panamera – the first 4-door sedan in Porsche’s history – delivers sports car-like performance and engineering finesse that make its bloodline difficult to deny.

Purists may hold fast to their belief Porsche should make sports cars and nothing else. But that barrier was obliterated with the 2003 launch of the Cayenne cross/utility vehicle, now the best-selling Porsche of all time.

To survive long-term, the auto maker needs to offer a lineup that goes beyond the 911 and Boxster, so look for Porsche to continue morphing closer to a full-line player in the luxury sector – like it or not.

Some may find the Panamera’s proportions just too awkward, with its Platypus-like snout and J. Lo-like bulge in the back that’s meant to give the sedan a family resemblance to the 911 and still leave room for four adults and cargo.

Let’s just say pictures don’t do the car justice; the Panamera plays better with the naked eye than the camera lens. And any resistance to the concept of a Porsche sedan or aversion to its physique quickly melts away once behind the wheel.

The Panamera measures 195.6 ins. (497.0 cm) in overall length and is 76.0 ins. (193.1 cm) wide and 55.8 ins. (141.8 cm) tall, making it shorter and narrower and casting a lower profile than an Audi A8. It rests on a 114.9-in. (292.0-cm) wheelbase, about 6 ins. (15 cm) shorter than an A8 or BMW 7-Series.

Even in its base form, the Panamera is as close to a sports car as possible for a fullsize sedan. But there are enough gadgets and gizmos available to take that up a notch or two for a driver blessed with an empty cabin and irresistible road ahead.

With the exception of its powertrain – and even that is heavily modified – the front-engine/rear-drive Panamera is all new from the ground up.

“We started with a clean sheet of paper,” says Stefan Utsch, Panamera program manager, who wryly points to the badging on the hood and wheels as the only things shared with any other Porsche.

The engine is the direct-injected 4.8L V-8 that powers the Cayenne, but Utsch says Porsche went with aluminum bolts and magnesium valve covers, among other tricks, to lighten the powerplant for better fuel economy. Porsche also had to reconfigure the engine for the lower-profile placement in the sedan, running the front axle directly through the crankcase.

The base version of the direct-injected gasoline V-8 pumps out 400 hp and 369 lb.-ft. (378 Nm) of torque. Adding the optional twin turbos pushes output to 500 hp and 516 lb.-ft. (700 Nm). The standard engine proves to have plenty of power, but the Panamera Turbo is an awful lot of fun pedal-to-the-metal in the long straightaway to the finish line here.

Both engines are mated to Porsche’s PDK dual-clutch automatic that is a little balky at launch but shifts nearly imperceptibly, either automatically or manually (including via steering-wheel paddles) through its seven gears.

There’s enough muscle for a 0-60 mph (97 km/h) run in just 4.8 seconds with the base model, while the turbo version will knock that off in 4 seconds flat. Top speed is 175 mph (282 km/h) with the naturally aspirated V-8 and 188 mph (303 km/h) with the turbocharged engine.

Among the high-tech toys onboard is an optional sports exhaust system that, with a touch of a console-mounted button, muscles up the exhaust note to the tune of a 911 in heat. The sound effect is varied depending on road and engine speed and the gear selected, and at wide-open throttle the car easily could be mistaken for a street rod.

Porsche employs a couple of other electronic tricks to help transition the car from sedate luxury tourer to performance coupe. A Sport button adjusts the engine shift points to hold gears longer, and a shock switch stiffens the 4-wheel adjustable air suspension to vary ride and handling.

’10 Porsche Panamera
Vehicle type Front-engine, rear-/all-wheel-drive, 4-passenger sedan
Engine DOHC 4.8L V-8 with aluminum-alloy block/heads
Power (SAE net) 400 hp @ 6,500 rpm
Torque 369 lb.-ft. (500 Nm) @ 3,500-5,000 rpm
Compression ratio 12.5:1
Bore x stroke (mm) 96.0 x 83.0
Transmission 7-speed dual-clutch automatic
Wheelbase 114.9 ins. (292.0 cm)
Overall length 195.6 ins. (497.0 cm)
Overall width 76.0 ins. (193.1 cm)
Overall height 55.8 ins. (141.8 cm)
Curb weight 3,968 lbs. (1,800 kg)
Base price $89,800
Fuel economy 16/24 city/hwy (14.7-9.8 L/100 km)
Competition Audi A8, BMW 7-Series, Mercedes S-Class, Lexus LS 460
Pros Cons
Sports car handling Odd proportions
Max headroom Form rules function
Little pain at pump Price

Then there is the Sport Plus feature on Turbo models that provides even more kick, increasing boost pressure, adjusting shift points to even more aggressive settings, changing the rear spoiler angle and delaying intervention by the stability management system.

The Sport Chrono package adds a stopwatch to the top of the dashboard to time your laps and includes launch control that cuts 0.2 seconds off a 0-60 mph sprint. Activate the system, apply the brake with your left foot and mash the accelerator to the floor with your right. As the brake is released, the Panamera accelerates all out.

Porsche didn’t give us a chance to test the feature, but it was amply demonstrated during a series of hot laps with professional drivers.

All-wheel drive is optional with the base engine and standard with the Panamera Turbo, and it provides sure footing through the curves here. But while AWD would be a plus on the street, particularly in Northern climes, truth be told, the livelier rear-drive model proves more fun to flog around the racetrack.

The Panamera Turbo gets 19-in wheels, optional on the Panamera S and 4S, which come with 18-in. wheels as standard. There also is a pair of 20-in. wheels available, including a set borrowed from the '10 911 Turbo.

The light-alloy wheels are fitted with specially developed, smooth-riding Michelin tires. Michelin says it spent two years and produced more than 2,000 prototypes in engineering the new tires, which demonstrate plenty of grip.

There’s a long list of additional features available, including dynamic headlamps that follow the road, stability management, antilock brakes with brake assist, adaptive cruise control, start-off assist (holds the car on a hill after the parking brake has been released), electronic air suspension with individual controls at all four wheels, navigation system, cabin filtration and rear-seat temperature and lighting controls.

There are eight airbags onboard, including those to protect front occupants’ knees and curtain airbags that stretch the length of the cabin. Front seats come standard with side-impact airbags, while those for the rear-seat passengers are an option.

Nearly taking your breath away as you open the driver’s door for the first time is the unique, expansive, switch-laden center console that stretches front to back.

There’s no I-Drive-like interface here, just clusters of buttons to control everything from the climate system to rear-spoiler position. It’s a striking display some might consider cluttered, but it solidifies the Panamera’s cockpit feel and doesn’t require a 6-in.-thick instruction manual. Even at track speeds, it’s possible to locate a desired function quickly.

Instrumentation evokes the 911, with rounded gauges, including a center-mounted tachometer, and left-hand ignition. There’s no fancy start button here, but the key doesn’t have to be inserted into the ignition. As long as the key is present, the driver can open locked doors and fire up the Panamera by rotating the ignition lock.

There are five different wood trims available, as well as brushed aluminum and carbon-fiber accents. Several different grades of leathers are offered in multiple colors.

Because the console runs the length of the interior, there’s room for four, not five, passengers. The supportive, 18-way adjustable front seats mimic the contour of the 911’s buckets, but are more luxurious and include a power-adjustable leg support that extends forward from the base of the seat. Rear seats can recline slightly, and their positioning provides occupants with an unusually clear view of the road ahead.

A low seating position translates into plenty of headroom for both front and rear passengers. Optional are heated and cooled seats, which provide some relief here on a fairly warm fall day.

Entry and exit are made a bit easier in tight spots by doors that stay open at any angle.

There are two optional sound systems, a 14-speaker Bose unit for $1,440 (standard on the Turbo) and a 1,000-watt 16-speaker system from Burmester Audiosysteme GmbH, selling for $3,990 on the Turbo, $5,690 on other models. The Bose system is terrific and will be more than adequate for most. But the true audiophile with the financial wherewithal will want the Burmester, which offers another whole level of crispness and clarity.

Cargo capacity at 15.7 cu.-ft. (445 L) is 4 cu.-ft. (115 L) less than the trunk room in a Mercedes S-Class, but rear seats fold flat to expand that to 44.6 cu.-ft. (1,263 L).

“You can fit two bikes, without taking the wheels off,” Utsch assures.

The AWD Panamera 4S weighs just 4,101 lbs. (1,860 kg), about 220 lbs. (100 kg) lighter than the aluminum-intensive 4-wheel-drive A8 and 529 lbs. (240 kg) less than a 4Matic S-Class.

To minimize mass, Porsche uses aluminum for the hood, doors and trunk lid, as well as the frame around the rear light clusters and corner section of the luggage compartment. Plastic is employed for the trough in the luggage compartment.

Fuel economy is rated at a respectable 16/24 mpg (14.7-9.8 L/100 km) city/highway for the Panamera S and 4S, thanks in part to its first-in-class stop/start system supplied by Robert Bosch GmbH. The Turbo model achieves 15/23 mpg (15.7-10.2 L/100 km). All of the Panameras dodge the U.S. gas-guzzler tax.

The Panamera officially goes on sale in the U.S. Oct. 17, starting at $89,800. The 4S stickers at $93,800 and the Panamera Turbo starts at $132,600.

Porsche largely has succeeded in creating a car with two distinct personalities: a fun-to-drive sports sedan when the opportunity presents itself and a luxurious cruiser when hauling passengers is unavoidable.

That’s forced some packaging compromises compared with other fullsize luxury sedans. But well-heeled buyers more interested in driving than carpooling will find the Panamera’s genetic makeup a winner.