I agree with the posts about being a bit too big for a 2 door but...I did drive an M5 a couple of weeks ago which got me thinking about the M6.
That thing was awesome on a straight line and on ramps on freeways it was like going on a roller coaster. Head snapping power is addictive. It did feel heavier on the curves compared to my last e92 coupe which I will forever miss but I expected it anyway. It still felt poised on the road and around curves but probably not as fun as my M3.
I'm not a Porsche kind of a guy as I've had 6 BMW's and am pretty loyal to the brand. But as stated above, the Z06 is an animal as well so it's on my radar as well. I just don't like seeing the Chevy emblem on the front....