Porsche debuted its 911 GT3 RS hybrid, which uses a flywheel rather than batteries to store electricity, at the Geneva auto show earlier this month. The system allows the German racer to recover kinetic energy when braking, and quickly release it again to power the engine or to give it an additional boost.
The 2011 Ford Mustang is the first production car to produce more than 300 horsepower and get more than 30 mpg highway. The car's official EPA rating, completed earlier this month, has the V6, automatic transmission version achieving 31 mpg highway. The engine gets 305 horsepower.