I got a problem with my new exhaust. I hear a rattling around 3k RPMs. My friend matt commented that my exhaust is really close to my rear differential. I'm thinking its getting some metal on metal contact and that is casuing the rattle/buzz noise. Anything else could be causing this? I ordered some heat wrap to try and fix the problem and if that doesn't work I was gonna order some urethane hangers(kartboy). Any help would be greatly appreciated.