A little like the 3 Series, the BMW 5 Series is a model of adaptability. It's available with four engines: a 4-cylinder turbo, a 6-cylinder turbo, a diesel or an 8-cylinder. If you want to give your passengers comfortably seated in the back seat a scare, opt for the M5 that, with its 560-horsepower turbocharged eight-cylinder, is sure to make their hair stand on end.