– 5.2 liter V10, 500+? horsepower. The engine is believed to be derived from the Lamborghini Gallardo’s V10. Previously they were testing a twin turbo version akin to what’s in the Audi RS6, but the prototype twin-turbo V10 car caught fire and burned to dust last year.
-6.0 liter V12 TDI, 500 horsepower, 737 lb ft of torque. This diesel supercar was in the Audi R8 Le Mans concept car from the Geneva and Detroit auto shows. And Audi just a few weeks ago confirmed that the monster oil burner will not go into production.
-4.2 liter V8 TDI, 326 hp, 550 lb ft of torque. Unlike the V12, this diesel sports car IS going into production, according to Michael Dick of Audi.
Source: The Truth About Cars