great thread, excluding the 6MT vs. DCT conjecture.
a couple comments to add:
1. not sure where i heard, but i think the current Roundel, mention of a M3-GT variant as a possibility
2. i remember comment that BMW will move to DCT for larger cars and stick with 6MT (pun!) available for smaller cars. not sure where the M3 falls on the big/small issue, but if the new M5 has an available 6MT, you'd have to assume the F3X will also have this available.