I think we are going to be seeing lots of fake M135i, M335i, M535i... on the road once they are released in the US, it will be easier than ever for "posers" to fool people since BMW will be doing it themselves! In the past it was easy for someone to spot a fake, most of the time just the bumpers and pipes would let you know what it really was.
I understand the M Sport package and have it myself on the X3 (mainly because I love the look of the bumpers and black trim plus there is no X3M yet), BUT I wouldn't want the back of my car to say "M" in any fashion, even with a performance boost I wouldn't want it to say M, unless it was specifically designed to be an M car. I am pretty sure on all Mercedes AMG "packages" they don't say AMG on the rear badges, same with Audi and the RS/S, although I think they do have an "S Line" badge. If BMW NEEDS to put something on the back I would much prefer a "M Performance" badge than it to say M next to the model, if that makes sense?
They are doing this because it will be a cash cow but they also must realize that a ton of people bought M's because they were unique and a status symbol, what will those people buy when M can be had on a much cheaper model? The person who doesn't care about performance but bought an M3 because of it being a status symbol can now just buy an M335i for $10K less and 99% of people on the road will have no clue there is a difference.