I recently lowered my 2011 mustang and I am running the Kooks header, kook high flow cats xpipe, and the magnaflow comp system 3". I now have an exhaust that rattles. Took it to Kens Muffler Shop to look at it and I noticed the over axle pipe hitting the rear end and the vent on the rear diff leaking. He said that there was nothing he could do for me but I am not just going to give up. The exhaust sounds loose but I can not find anything abnormal. Does anyone have some suggestions? I need a good shop that's used to dealing with these issues.