There have been some rumors in the past that BMW would be leaving ALMS and focus only on DTM. More recently rumors have started that BMW would stay in ALMS but switch from the M3 to some sort of Z4 based vehicle. However there hasn't been much info from BMW regarding if they will even participate next year. I am glad to report that BMW has confirmed via twitter that they will continue racing in ALMS. This still leaves the question of what car they will use. Personally I doubt they will continue to use the E92 M3, and I am 99.999% sure they wont run a F80 M3 since it wont be released in time for ALMS duty. So that leaves the Z4.
However there is one problem. The only motorsport version of the Z4 is the Z4 GT3 which uses a 4.4L V8. Obviously since there is no Z4M with a V8 this doesn't follow spirit of ALMS's rules. But since the Viper got to use such a large displacement engine maybe they are willing to come up with compromises to keep manufacturers in the series.
"@BMWUSARacing: Quite a good ending to a very competitive season! Now, the preparations begin for the 2013 Season."
"@BMWUSARacing: Thank you to all our loyal BMW fans. We do this for you! Stay tuned for announcements on next years program before the end of the year."