I too believe there will be a carbon roof eventually on the M2, just not on the first release. They will probably save it for an M2 GTS or like.
Rumours by Scott26 saying the next generation 2 series model could all be running on a front wheel drive platform, anything further to add Scott? If true, way to kill off a great car!
http://www.2addicts.com/forums/showthread.php?t=1034302