Mounted where it is, does it interfere with passenger legs? It looks like it's sticking out too much. Very prominent.
I'm looking for an extinguisher to mount in the cabin somewhere but I don't know of a good place where it is out of sight. In the E46 you could place it under the seat and the one BMW sold with their brackets fit perfectly or you could place it in the first aid box they sold that mounted under the seat. (Maybe it would bounce around, idk). Unfortunately, the subs are under the seats in the E9x and there just doesn't seem to be any room there. That's not to say the one being sold by BMW is not sexy looking.
I think I'll be going with a larger (and cheaper) one like the one in TrackRat's post, and mounting it in the trunk.
I've been assimilated. 6MT/ZPP/18"/PS extended.