The new M3 coupe/cab/sedan will sell just fine. You can't even get a coupe or cab here without special ordering it. I am not too worried about the US sales as you guys are going through a slow period right now and once things turn up you are going to see all luxury manufacturers #s go back up. Owning a BMW has never been more affordable then in today's society and with the tech sector allowing younger individuals to make good $$ it only makes demographic sense that this generation of M3 will surely out-perform its previous rendition.
R8GT Spyder '12 / M5 '13 (MT) / Cayenne S '12 (Baby mobile