I recently picked up an '88 M3 that I'm setting up for autocross...and there is a strange rattling noise coming from the bottom of the car. It sounds like it's coming from the right rear wheel...and only when I hit a bump. I've had the car up on jackstands numerous times and I just can't find anything loose down there. It's a metallic clanging sound that happens when I go over the slightest bump. Does anyone have any possible leads for me? I checked the heat shields, suspension components, brake components, and exhaust mounts, and everything feels solid. This is driving me nuts. Any help is greatly appreciated. Thanks!