Hmm, I'm guessing you can fit 19's but suspect you may have to do some shaving. Just make sure you go to a reputable shop that will make sure you are set up right and not just sell you rims that look good. I did that the first time with one of my Civics and I rubbed like a mofo. Be a cryin shame with such a piece of art like your Bimmer.
With that said, my rule of thumb when buying rims was to go two inches up from stock and that never caused any issues for me.
When you get your rims, make sure to throw up some pics... B)
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