I got to drive the first M6 from our dealer on monday. It came in for its 1200 mile service and from my compairison of driving the M5 and the M6 is they really are 2 differnt cars.
The M5 reallys plants you back in the seat, the gear shifts hits harder and you really feel like your going fast.
They also come with the active side bulsters that hug you in turns which the M6 dont come with.
The M6 doesnt feel fast, but my the time your hitting 3rd your already doing 70mph almost to 80 so it is a very quick car. I guess since you cant see the hood while you drive a 6 makes it seem slower, while the M5 you can see all the way to the emblim.
The M6 does have a better turing response and it feels much tighter in the corners. Also having the 8.5 grand rev limit is almost ridiclous. By 7grand you want to shift, but you still have anotehr 1500rpm's to go and it just keep on pulling harder and harder.
Everything on the M6 is designed for the track. Theres no electronic sway bar control, just a regular bar with end links. The brakes are gigantic and stop you in seconds. Some of the best brakes Ive ever driven with. The traction is unbeatable, going around 90* turns at 60mph + and no tire squeel is just jaw dropping, theres no brake fade (not like I was beating on the car bad enough that it would accure) but the brakes had the same stopping power time and time again. Only problem is the price, I havent even looked at the sticker sheet yet but Im sude its near the 105k+ mark.