Today I had the privilege to be invited to a BMW experimental M6 Gran Coupe event. At the beginning of the day we got to take M5 and M6 cars on a short autocross course. (3 trips full speed after 2 instructor lead with radio support.) Later, we took out 640xi, 650xi &i, 750li, 760li on the road course. Keep an eye out for the event in your area. It was a blast. There were 16 of us driving almost non-stop from 0900 - 1200.
The M5 was a beast on the autocross course as well as the M6 convertible.
(All of the M cars had the carbon ceramic brakes.) On the road course I enjoyed the 650i M package and the 760li the most.