The M6 Gran Coupe (M6GC) was spotted with little camouflage revealing a sculpted roof (which is carbon fiber underneath the camouflage, similar to the 6 Series Coupe) and a set of carbon ceramic brakes for the first time. The M6 Gran Coupe is expected to arrive as a 2014 model year and will debut at the 2013 Detroit NAIAS in January 2013 or the 2013 Geneva show in March 2013.
Source: Bimmerpost