Either get an M5, or make your vile offspring climb in the back of your M6 with the proper number of doors. Why make a 6-series 4-door, with "Coupe" in the name no less? Are we going to see a 4-door version of the 4-series? Why not put a panoramic sunroof on it and call it Cabriolet, after all, what's in a name? To be…