As with many M division products, the latest M6 switches from normally aspirated power to a twin-turbocharged engine. It also loses two cylinders, moving from the V10 to the latest 4.4-litre V8 but gains around 50bhp in the process.
The new unit gives the M6 552bhp and 502lb ft, and that huge amount of torque is available between 1500rpm and 5750rpm, a considerably wider spread than available from the previous engine.
The M6 coupe can hit 62mph in 4.2 seconds, while its drop-top version takes 0.1sec longer. Both cars are limited to 155mph.
The new car gets engine stop-start technology and a brake energy-regeneration system, which help the M6 coupe return average economy of 28.5mpg with emissions of 232g/km; the slightly heavier convertible delivers 27.4mpg and 239g/km.
Styling changes over the regular 6 Series include new front air intakes, a revised grille, a front axle that's 30mm wider, M-division 19-inch alloys (20-inch items are optional) and a rear diffuser.
The chassis set-up includes revised power steering, with a variable ratio to improve low-speed agility, and BMWs Dynamic Stability Control, which allows the driver to specify the amount of assistance offered by the cars safety systems.
Both the coupe and convertible get 400mm front brakes and 396mm rear brakes; a 410mm/396mm carbon-ceramic set-up will be offered as an option for the first time on the M6.
Standard equipment includes two-zone climate control, heated seats, extended Merino leather trim, sat-nav with a 10.2in colour screen, and the M-specific head-up display. Both cars go on sale on September 15. The coupe will cost 93,795, while the convertible will be 98,995.