Next 911 prototype doing some cold weather testing in Scandinavia and revealing new rear shape.

Here are the latest rendering and spy shots of a virtually undisguised next-generation (2012) Porsche 911 having itself a winter workout in a Scandinavian wonderland.

Porsche is still seeing fit, though, to try to hide some of the details of the newly shaped rear end of the car, but the photos do provide a general idea of what's in store for the new back-end look of the car.

There are few other secrets left on the Porsche brand's core model as we've previously reported on many of its details. The next 911 will be 4.49 meters long - 56 mm more than the current model with 10 mm extra wheelbase. The car will also stand 11 mm shorter.

The 3.4 liter entry-level Boxer engine (down from a 3.6 liter unit) has an output of 350 PS (257 kW / 345 bhp), good for a 0 to 100 km/h sprint time of 4.8 seconds and a top speed of 289 km/h (180 mph). The smaller, more-efficient unit will reduce fuel-economy by 13 percent to 8.5 liters/100 km (27.7 mpg-US).

The Carrera S gets a revised 3.8 liter unit with 400 PS (294 kW / 395 bhp). The 0 to 100 km/h sprint takes 4.5 seconds and a top speed is 302 km/h (188 mph). Fuel-economy will be down 14 percent to 9.1 liters/100 km (25.8 mpg-US).

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