i run a set of 18" x 8.5" BBS RSII on my standard E30 M3 no arch mods at all, however the tyres are 225,35,18 and do not rub anywhere. they look the dogs dogglies but the ride is as hard as nails! The car Goes to Germany once a year for a track day at "Nurbergring" and is always the fastest car over a lap even though its not the fastest down the straights. A good choice of wheel and tyre combination if you can stand the hard ride. Saying that roads in the states are far far better than in England!