X4M and X3M are merged so lets do it!
So are we going to merge the base X3 and X4 threads too? If that's the case then why even have an X4 forum?
The X3 and X4 (and the M versions) are two separate models that just happen to have been launched at the same time. And if there is an argument to have the X3 and X4 in the same thread, then you could make the same argument for having just one 3 Series thread which contains every iteration of that, from the sedan to the Gran Turismo to the Touring. But because they were launched at different times, nobody is requesting that are they?
Put it this way. If the X5 M was launched today, and then the X6 M was launched next month, nobody would be saying "post any comments about the X6 M in the X5 M thread" would they?