17x11??

If I get 17x11's in the rear with 315/35's will I have any rubbing issues with my ground effects what would be a good offset?

there is no clearance issue with the ground FX...because the tire diameter is the same as stock. so it the whole wheel should sit in the same position in the wheel well. the rubbing issue is with the sidewall on the inside of the tire against the wheel well.

and basically ever car is different. some guys say they rub constantly...others (like me) have 3/4" of clearance all the way around

Read the sticky for more info.