I borrowed this from a Bimmer E46 M3 web site:
The M3 sits on 18-inch M-style alloy wheels (8.0-inch wide front and
9.0-inch wide rear), with appropriately sized high-performance tires (225/45 ZR - 18 front and 255/40 ZR -18 rear).Will I be able to successfully install this combo on my 330ci? Is there a reason why it won't fit? i.e. different diff :) larger/smaller wheel wells, different suspension width? I'm not saying I want to run this combo, but since I will be buying these wheels and tires via mail-order, getting it wrong would be expensive. I don't have the luxury of trying out different sets. I have to get it right the first time. The E46 M3 runs different size wheels and tires in the front and rear. Is there a reason why doing this on my car would mess-up my handling and not mess-up the M3 (as another said earlier)?
I appreciate your indulgence while I get my feet wet with a BMW.