Video: 2011 BMW M5 testing at the Nürburgring

Last month we brought you spy photos of a lightly disguised next-generation M5 from the legendary Nürburgring.

What we have here is a video showing this ultimate sedan going through heavy testing at the Ring.

That video should be clear evidence that new M5 will pack a twin-turbo V8 not the naturally aspirated V10 as the current model.

Just turn up the volume to hear the 4.4-liter twin-turbo V8 whistle when the car accelerates on straights. This twin-turbo V8 packs 555 horsepower in the new X5 M/X6 M. No information will BMW up the power for the M5 or not.

Rumor is that for additional power new M5 will feature a KERS system found in the Formula 1 cars. The system shuts down cylinders while city driving and also has a boost button that allows the driver to unleash all the energy stored up.

At the moment two gearboxes are on the table: an updated 8-speed dual-clutch gearbox (DCT) or a more advanced 8-speed SMG.

New 5-Series will be launched at next year’s Geneva Motor Show. M5 is expected earliest at the Frankfurt Motor Show next fall or at the 2011 Geneva Motor Show.