For 2011, along with the standard 3-series, BMW is going to be updating the M3 Coupe and Convertible as well. The most obvious different is the inclusion of the new LED tailights to the M3 while leaving the current design on the front of the car alone. IMO this is the perfect combination (hopefully a retrofit won't be too difficult).
Other changes which are not so obvious in these pictures are interior changes such as little updates on the trim pieces with updates to the iDrive system and screen.
Make sure to take a look at southlights post containing the official CGI photos of this car from BMW: http://www.m3post.com/forums/showthread.php?t=346270