Here is a link to a thread on here from a company we have all heard of who did a car for a customer with larger wheels on a Factory suspension/stance car.
20x10's are a good size imo for the rear if you want to go larger Cool however IMO 20x10's are a little large for the front just my .02 cents
9.5 is large enough.
http://www.camaro5.com/forums/showth...ght=HRE+wheels