i recently installed test pipes on my car and noticed a reallly high pitched rattling noise...i had the car checked to see if its an exhaust leak and they said that it wasnt and that it was a rattling in the y pipe...when they banged on the y pipe no noise was produced...he said it was probably something that broke in the resonator of the y pipe and is rattling because the test pipes are allowing more air into the y pipe than before...i kno its not the rasp because my test pipes rasp is a distinctly different noise...has anyone else had this problem??