Couple things. BMW guys do this so the roof looks like the cf roof on the new M3. I think it looks ok.

I've seen a few cars with long term matte black vinyl overlays and they are actually remarkably easy to maintain. This guy had his on for over a year and it looked fine:

 

vlads car.... the matt black is a really nice, but i think if you have a sunroof, the matt would clash with the sunroof....honestly, i want the matt black colour because it looks so much more unique, but it just doesnt go with g coupes..