?? You can install whatever fits on the replica rims depending on how wide they are (7 1/2", 8"...) .... I'm running offset 17" M5's 255's on the rear, 235's up front (I forget my sidewall aspect ratio... still have my winters on) Really, 225's are nothing on M5 replica's... take them to a tire shop and they'll fit them properly. 255's are awesome... 225 is nothing.
BTW, if you're not busy on sunday, there's a BMW cruise that starts in Pickering (the last one started in Mississauga, so it's only fair to start in the east end this time) Expecting about 100 BMW's!!
http://www.maxbimmer.com/forums/showthread.php?t=104693