Ever since I installed the APR catted downpipe to my GTI I’ve noticed a tinny, high pitched, metallic, air-puffy like sound that comes from front-mid section of the exhaust when accelerating next to walls or other cars. I’ve got it welded in so not a leak and I’m almost certain it’s not hitting anything and I’ve checked all the heat shields— so, is this normal? Would exhaust wrap maybe damped our those unpleasant noises? Cold starts in the morning is when it sounds the worst. When parked on grass, can’t hear it at all, but when parked on solid surfaces sounds like it’s reflecting off the ground.