I've been having issues with a squeaking noise coming from the RR of the car ever since I had my GTHaus exhaust installed. I've checked all of the bolts and everything is tightened down. I had a stud break when I was checking torque on the RR hanger under the bumper. While I was waiting to have it fixed I didn't notice that it was squeaking, but after the dealership fixed it it started squeaking again. I've tried spraying the rubber hanger behind the RR tire and the hanger under the bumper with silicon spray thinking that would fix it, but it didn't. At this point I'm completely stumped and don't know what to do. It sounds like medal on medal but only happens when I am keeping the RPMs above 3,500 and driving very spiritedly. The exhaust does not come in contact with any of the heat shields and is not rubbing on the body. Once I hear it, if I keep my foot out of the gas and not drive as spiritedly the squeaking goes away after about 30-45 seconds of normal driving.

Any help would be appreciated.