The M550i is powered by a twin-turbo 4.4-liter V8, making 523 horsepower, 553 pound-feet of torque, all sent to the wheels via an 8-speed automatic transmission. 0 to 60 mph is just 3.6 seconds, and even features launch control! The M5 makes more power, but torque output is the same for the M550i, M5 and M5 Comp, making this one serious contender.