I think it would be a great move. Definitely go test drive an F30. You might just fall in love with it.
Part of me thinks that in 1-2 years, they'll put the B38 3cyl into the 320i, and it could be the best bang-for-the buck with a tune/mods. You'll have a VERY lightweight engine that is set way back in the engine bay. If they could get that thing up to 225HP with a free-flowing exhaust, it would be pretty fun to whip around a track.