http://www.auto-motor-und-sport.de/d/83098
314hp, 730Nm, 0-100km/h 6.1s, limited to 250km/h. twinturbo V8.

240 kW (326 bhp): With this extremely impressive horsepower output, the new Audi A8 4.2 TDI quattro puts itself ahead of all the other diesel-engined cars on the international market. The entirely redeveloped 4.2-litre, eight-cylinder biturbo engine accelerates the lightweight saloon with its aluminium body from 0 to 100 km/h (0 – 62 mph) in just 5.9 seconds. The top speed is electronically restricted to 250 km/h. In addition to these dynamic qualities, the new power plant displays the kind of refinement that sets standards even in the top segment of the motoring world, and ennobles the A8 4.2 TDI quattro, turning it into the perfect long-distance touring saloon.
Update:
http://www.germancarfans.com/news.cf...id/2050518.006
More details about the mercedes
http://www.germancarfans.com/news.cf...id/2050519.004
More details about the audi A8 4.2TDI