I wish the brakes were larger. Would have been nice if they took the units from the m5/6. I am sure these brakes will work fine and are probably lighter. The car looks very narrow to me though. I think it will be thinner than the sedan just as the e92 was to the e90. I am happy to see it using that super sexy steering wheel from the m6. So glad to see that. As for the rear bumper the exhaust cutouts are very sloppy and the bumper is very thin. I think this is a f32 bumper that was cut to fit the quad exhausts. I am sure the final bumper will thicker/beefier and have some kind of functional Aero design. Lastly as for the exhaust itself I think the tips are ugly but I am glad to see that the muffler portion looks much smaller than the previous e46 and e9x M. I am willing to bet it will hide nicely behind the final rear bumper design and hopefully it's a good bit lighter.
Oh and the wheels I think will be final. If you look closely you can see the ///M badge on the wheels.