I had some B5 RS4's that were 8.5 wide, one had a 225/35/18 tyre on, it was fine. no problems at all, even on the naff cambridgeshire country roads... if it wasn't for the offsets i'd still be running them. so they should be fine.
the tyre on the left is a 225 on a 8.5 wheel, and a 255 on the...