Audi is marking the 25th anniversary of its TDI engine by creating the RS5 TDI concept, unveiled at AMI Leipzig. Based on the RS5 Coupe, the concept swaps the 4.2-liter V8 for a 3.0-liter twin-turbo V6 TDI that comes equipped with an electrically-driven supercharger Audi says will eliminate turbo lag. Rated at 385 hp and 553 lb-ft of torque, the engine is mated to an eight-speed auto and quattro all-wheel-drive system, enabling the coupe to sprint from 0-62 mph in four seconds, hit a top speed of over 174 mph, and return 47 mpg.