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 in Elkhart Lake, WI, 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.

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 is shorter and narrower and casts 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. The engine is the direct-injected 4.8L V-8 that powers the Cayenne, but Porsche went with aluminum and magnesium to lighten the powerplant for better fuel economy.

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 at the track.

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.

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.

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.

All-wheel drive is optional with the base engine and standard with the Panamera Turbo, and it provides sure footing through the curves. 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.

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.

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).

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.