You don't have to have 20's to clear the Brembo's. Hell, Bogart and Weld make 17" wheels that will clear them. Our stock 19's will not clear them without spacers though, and our tires are about an inch shorter than the Camaro.
'09 PSM G8 GT w/ Premium & Sport packages.
Go: Kooks 1 7/8" LTs, Corsa, VCM OTRCAI, Rick Crawford's AirRam intake and ported TB, 3.27 gears.
Whoa!: CTS-V/ Camaro 4-piston Brembos, Hawk pads, DBA rotors, full Zeta II front and rear suspension swap w/ BMR goodies.
Show: 4300K TRS HIDs, LED fogs, VG Sharkfin, GXP diffuser, 10% tint, debadged, BC Coilovers, polished CTS-V wheels.