Dream Diesel
Audi Q7 TDI
Price: NA
Power: Diesel-powered, twin-turbo V12, 500 hp
Fuel: About 20 mpg
A descendent of the shockwave-creating R10 Le Mans race car built by Audi, this V12 diesel pumps out a reported 500 horses. That, Audi says, makes this version of the Q7 the world's most powerful diesel passenger car.