I recenetly purchased a 2003 GT with a 5-speed, I upgraded to Flowmasters, BBK off road x pipe and mil eliminators. Whats the deal with the x pipe, its all tight and no exhaust leaks and its not rubbing on the frame anywere but it makes a loud metal rasping noise at lower rpm's almost like a shield rattling noise but i have no idea, any info would help, thanks