Mercedes-Benz created the four-door coupe with the CLS; Audi and BMW just followed suit. Mercedes then created a hotted-up version of the CLS, using motors from AMG. And it's only now, after many years that Audi and BMW have responded with their own versions; the RS7 and M6 Gran Coupe respectively.
Both make 552 bhp; the Audi from a 4.0-litre twin-scroll turbo V8 with cylinder deactivation technology (effectively making it a four-cylinder under light engine loads) while the BMW makes do with a 4.4-litre, twin-turbo V8 made famous by the M5 saloon.
The Audi is a smidgeon quicker to 100 kmph, but both can hit 300 kmph given the right stretch of road. Where the RS7 is more in your face, the M6 Gran Coupe uses curves to entice. Both cars are likely to hit Indian roads by 2014 with price tags upwards of a crore of rupees.