was the car dropped? did you upgrade your suspension? I think the problem with a lot of people who get aftermarket wheels, especially 20's, don't take the offsets into consideration, the proper tire, and they don't upgrade suspension parts. I think using 20's you should go for new shocks and struts to compensate for the harsher ride. If you want to lower it, i would make sure i get an adj. panhard rod and some stronger LCA's while im down there