i have a 2000 elantra and i bought 15" wheels and tires about a month after i bought the car, every time i hit a slight dip in the road it sounds like the wheel is hitting the inside of my wheel well. i also have a dual 12" subwoofer box in my trunk....any guesses on how to fix this problem without taking out the box?

 

you could get some firmer Coil Springs or you can Get some Stiffer Shocks, and if you plan on lowering the car and getting an some adjustible coil overs it should stop with the adjusditbles.