But ... there's already an M6 Coupe, you say. Yes, there sure is, but there's no Gran Coupe, which will live in between the M6 and the M5, as a competitor to the Audi S7 and the Mercedes-Benz CLS63. A direct-injected 4.4-liter twin-turbo V8 will send 560 horsepower and 500 lb-ft. of torque to the rear, controlled by a seven-speed dual-clutch transmission with an Active M differential.