i am getting some custom piping for my exhaust. i am doing 2.25 from the cat back, and getting some kind of muffler (Greddy or Comptech or along those lines). anyway the guy who is bending the piping and everything for me said that i would need a resonater and that if i didnt have one, the car would make an annoying ringing noise. is there any truth to that? if so, where can i get a resonater?