I just re read everything....you say this only occurs with your aftermarket wheels, not your stockers...this rules out ball joints, tie rods, wheel bearings, and pretty much everything.
then you put on your 20's and they rub the caliper...my guess...you have the wrong wheels or lugs and it doesn't fit right, or somthing is bent. it really sounds like brakes, maybe cuz the rim or that side of the car has somthing bent. dude...if the caliper is rubbing, its gonna make a sound...thats prolly what your hearing...get your wheel and suspension looked at on that side cuz somthing ain't right.
if you switched wheels and the other wheel doesn't rub....its the wheel.
if that side rubs, no matter what wheel it is, its the suspension