The all-wheel-drive Mercedes-Benz ML63 AMG is the flagship of the mid-size luxury SUV lineup. The fully redesigned, highly fuel-efficient ML63 makes 408 horsepower and 500 lb.-ft. of torque and features a 6.2L V12 engine with twin turbochargers, cylinder deactivation and a variable valve timing system that opens exhaust valves on each side of the engine to give it an even more powerful sound.