Well if you look at Crucial Crossfire's car in the March Ride of the Month thread he's got the H&R Cup Kit with 20's on all 4 corners and he did say he had to roll the front fenders a little bit to not rub.

If you don't want a camber issue then don't drop the car. The rear can't be adjusted as easily as the front, but it can be done (crash bolt or something). You also won't be getting a smoother ride as well but it's the looks and performance that matter here. The Crossfire doesn't have the smoothest ride to begin with because of the wide/low tires.

I don't plan on putting 20's on my car but I also know I don't want the car completely slammed, so I'm going the Eibach route eventually which doesn't lower the car as much.