[Fen335i]

Apologies in advance if this was already covered in one of the threads...I searched last night for quite a while and never found anything that completely answered the question: How wide of a tire can you put on the 18 and 19" OEM wheels for the e92 M3? I realize I may need to upgrade to a wider wheel to get what I truely want, but does anyone know how big you can go without rubbing or losing performance? Does anyone have an pictures of this on their car? Thanks.