Go Go TurboSteamer
Looks like BMW has made a pretty interesting innovation in the realm of gas efficiency. In the past, one of the greatest inefficiencies of gasoline powered automobiles has been the amount of energy lost as heat through the engine exhaust. Now, they have invented a turbosteamer engine that uses the heat from the exhaust to power a second steam engine which assists the standard gasoline engine. Practically, this gives us a fifteen percent increase in gas efficiency at no cost. In addition to the gas efficiency, you also get some more torque.
The BEST news about this turbosteamer is that they can be fitted to existing models of BMWs, so should they decide to mass produce turbosteamers, they can refit their entire line of cars into being 15 more percent efficient.