Check out my thread on Bimmerfest:
http://www.bimmerfest.com/forums/sho...d.php?t=745383
I just changed out to the Dunlop SP Sport Maxx TT non-RFTs on my 20" 373M rims. I'm loving them so far, and this thread shows my solution to no spare.
The thread got a bit lengthy, so if you want the gist, read my first couple posts then skip to the last page and you'll see what I ultimately decided.