One of the biggest stars of the show, and most telling about the climate of the industry, is Audi's R8 V12 TDI Concept. As its name suggests, Audi engineers stuffed an efficient V-12 turbodiesel engine into their top-of-the-line sports car, producing 500hp and 738lb-ft of torque. (That'll get you to ticket speed in a hair over four seconds.) The engine is already compliant with Euro VI emissions rules that go into effect in 2014.

The styling enhancements are minor but hugely impactful. In addition to larger air intakes and nicely sculpted ground effects, there is an enormous intake set into the glass roof. The result makes the already aggressive standard issue R8 look downright anemic.

The marriage of high performance and high efficiency is not a new concept to Audi: their diesel powered R10 race car has been dominating Le Mans for the past two years. Two years ago the V12 TDI got some confused looks, but today the world is ready for its first fuel efficient supercar.