[KirkEvil]

I had the same problem when installing my ZR1 replicas with 315s. At the time I had the eibach pro kit and KYB shocks. I went back to stock springs to fit the tires and still had banging issues on the bump stops when the rear would rebound from large bumps in the road. I ended up cutting the whole bump stop bracket out (BFH mod)

If you want to try and keep the lowering springs, I suggest getting an adjustable panhard bar and some wheel spacers. 315s stick out some already, so the spacers will make it look more drastic. I also had some rubbing issues on the front rims on the spindle...that was my main reason for returning to stockers. damn replicas. Goodluck.