The BMW M5, launched 40 years ago, built its legendary reputation as the family sedan that chewed up and spat out sports cars. There have been many changes since.
It started out with an inline six-cylinder engine, then came a V8, then a V10. In 2011, it returned to a V8, though with turbocharging. Along the way it gained all-wheel drive. Now, in its seventh generation, its performance is boosted for the first time by an electric motor.
