chargespeed2.2l

I recently picked up a set of 18" advan model six. 2 rims came with 225 40 but they rubbed my stock strut so I am wondering if I should run 215 35 or will this be too dangerous and should i try to find 225 35. i can get a really nice deal on 215 35 but everyone is saying be care full. by the way my car is lowered by ground control so the fender isn't a problem to me just the strut.
just windering what you guys think
thanks
brian