Under the hood of the M6 Gran Coupe, BMW fitted the S63Tü high-revving V8 engine with M TwinPower Turbo technology that produces 412 kW/560 hp and 680 Newton metres (502 lb-ft) on tap between 1,500 and 5,750 rpm, while maximum output is developed between 6,000 and 7,000 rpm. The engine revs to a maximum of 7,200 rpm. 0-60mph is achieved in 4.1 seconds with a top speed limited to 155mph. The engine is matted to a 7-speed M Double Clutch Transmission.
The new Audi RS7 Sportback shares its drivetrain with the Audi RS6 Avant and has similar tech specs as the M6: V8 biturbo engine producing 560 horsepower and a top speed of 305 km/h. The RS7 also ouputs 553 lb-ft of torque.
Audi stays true to its DNA and the RS7 Sportback sends power to the wheels via the quattro system. The better traction and slightly more powerful engine allows the RS7 to run from 0 to 62 mph in 3.9 seconds.
In its base form, the Mercedes-Benz CLS63 AMG cranks out 557 horsepower and 531 pound-feet of torque from its 5.5-liter twin-turbocharged V8, sent to the ground via the automaker’s AMG Speedshift seven-speed transmission. The S-Model package includes a power bump that raises those engine output numbers to 585 hp and 590 lb-ft.
So which model takes the win? After measuring the three super cars in Powertrain, Chassis and Experience categories, the Audi RS7 takes the overall win, followed by the M6 Gran Coupe.
Here is a quick excerpt of the BMW M6 Gran Coupe review by Car and Driver and the full article can be found here:
BMW’s M6 Gran Coupe, on the other hand, faces an uphill battle. Its good looks can’t mask its close kinship to the disappointing M5 that placed last in our previous test. The Gran Coupe rides on the same 116.7-inch wheelbase, is powered by the same 4.4-liter blown V-8, and uses many of the same chassis components as its 5-series equivalent. Ponderous and plodding, the M5 shuns M-brand hallmarks of litheness and agility. But it should be noted that the M division’s philosophical approach with the Gran Coupe—how it tunes the bushings, springs, dampers, and anti-roll bars—sounds closer to how it views the sharper, sportier M6 coupe than the bulky M5 sedan.
We’ve been tough on the 6-series Gran Coupe, which isn’t even a coupe. You know, one more example of a brand-expansion scheme that’s out of control. But if Mercedes and Audi get a pass with their mid-size, four- and five-door “coupes,” why shouldn’t BMW? There’s an even better rationalization for the M6 Gran Coupe, though: It’s a stronger car than the M5.
That discovery is difficult for us to wrap our heads around, as the two cars are so similar. Yet the M6 Gran Coupe was repeatedly praised for its performance in this test, both subjectively and objectively. It recorded the fastest slalom time thanks to prodigious grip and unflappable stability. The optional carbon-ceramic brakes have great top-of-pedal response, and the M6’s stopping distance was just one foot longer than the RS7’s.
TEST DRIVE: BMW M6 Gran Coupe
The weighty steering isn’t as quick as we might like, but it reacts to every small adjustment. And in the Gran Coupe’s body motions, there’s no evidence of the M5’s nervous up-down clip. The Gran Coupe masters ride and handling trade-offs in a way that’s been notably missing from other recent BMWs. Even in sport-plus mode, the M6 retains a suppleness that’s absent from the Audi and the Mercedes.
The torque delivery from the 4.4-liter engine is especially linear, smoothing out the typical turbo wallop and placing both the power peak and redline higher in the rev range. The 552-hp M engine also sounds like no other turbo eight-cylinder. Higher pitched and with a prominent turbo whir, it’s part sci-fi special effects (some of the soundtrack actually comes from the stereo speakers) and part race-bred howl.