This month marks a new chapter in the history book for Porsche cars. After 60 years, the storied German automaker, known for building sports cars, adds two more doors and a new model with the arrival of the 2010 Porsche Panamera.

Panamera, named after a world-class auto race in the 1950s, is the manufacturer's first four-door car.

Earlier this decade, Porsche brought another "first" to their product line with the debut of the Cayenne sport utility vehicle. The decision to put a Porsche "off-road" drew skepticism from some brand loyalists.

But as the dust settled, it became clear that Porsche chose the right path. Today, Cayenne is the best selling vehicle in the Porsche lineup.

Porsche expects its Panamera performance sedan to fare equally well as it joins its automotive siblings, Porsche 911 Carrera, Boxster and Cayman.

Exterior styling reflects the family resemblance of Porsche 911 in Panamera's front end followed by a hint of Porsche Cayman in the tail lamps and hips of the rear quarters.

And because the interior has to keep what the exterior promises, form follows function with plush quad seating split by a classy full-length center console. Front-to-back head, hip and legroom is exceptional, courtesy of a 115-inch wheelbase.

The spacious leather-wrapped interior is accented by satin aluminum trim, genuine wood veneers and carbon fiber touches harmonized by a 13-speaker Bose 5.1 surround sound audio system.

Instrumentation and switches are refreshingly simple with at-a-glance button controls that bookend a tapered front console punctuated by a squat gear lever.

Out back, Panamera's full-figured rear hatchback styling yields 15.7 cubic feet of carrying volume with the 60/40-split rear seats upright and over 44 cu.ft. of available space provided when the second row is laid flat.

Porsche's newcomer comes in three front-engine models: Panamera S rear-wheel drive and 4S all-wheel drive, powered by a 4.8-liter V-8 engine to deliver 400 horsepower. priced at $89,800 and $93,800 respectively. Fuel economy is rated at 16 miles per galon, city, and 24 mpg, highway.

Panamera Turbo is infused with a 500 hp. twin-turbocharged 4.8L V-8 and all-wheel drive for $132,600. Mileage of 15, city, and 23, highway, is expected.

All models are governed by a seven-speed double-clutch transmission that delivers a dynamic driving experience with steering wheel shift controls for ultra-fast gearshifts without impeding engine performance.

Panamera's double-clutch system also showcases a 'green' side with a hybrid-like "auto stop" feature that shuts off the engine when sitting out a stop light, for improved fuel economy and reduced emissions. Releasing the brake pedal instantly restarts the engine.

Now with the 2010 Porsche Panamera, more can come along for the ride to enjoy thrilling performance in the lap of luxury set by a new benchmark with a sports car for four.