The 335is N54 has a different rating than the 1M N54 (320 bhp vs. 335 bhp). That 15 bhp bump for the 1M N54 indicates that itís not the same as the 335is N54 (you donít get something for nothing after all). So whatever modification that was done to get the additional 15 bhp could be the reason why it would not pass the 2012 emission regulations in the US, hence no 2012 1M.
As for the Z4 sDrive35is, will it be produced in 2012 (no Z4 production sheet was posted)? The Z4 sDrive35is N54 does have the same rating as the 1M N54, but that doesnít mean they are totally identical, either.