If you thought the horsepower wars were over in Germany, think again. Because while the elite cadre of luxury muscle cars have been getting smaller engines, they've hardly been getting less powerful in this constant game of one-upmanship. And the ball is in Audi
's court. For the latest M5, BMW
switched from a 5.0-liter V10 to a twin-turbo 4.4-liter V8, but while the displacement and cylinder count decreased (replaced by a set of spools), power increased from 507 horses to 560.