If you like the stretched look, the 225 will be fine. I personally prefer the 245/40 tires on my 18x8.5 wheels. Very minimal stretch, looks just right IMO. In my experience, you'd need to roll the rear fenders at stock height to avoid rubbing with the 245/40 with rear seat passengers.
MODS: PW TMIC, Cobb catted DP, HKS cat-back, AVO filter, Bren e-tune; Konis/Epics, Advan RCII