The basic difference between a Z85 and a ZQ8 besides the wheels is suspension and painted grille and bumpers. You can get a Z85 with the Street Pak option to get the painted grille and bumpers. The wheels will fit without any problems whether you get 2004-2006 ZQ8 wheels (17") or 2007 ZQ8 wheels (18"). Just understand that the wheel to fender gap will be about .5"-1" bigger due to the smaller diameter of the ZQ8 tires if you keep the stock Z85 suspension.