I am currently running 2 1/2" with straight through resonator and supercat muffler. The noise from idle to off idle and back to idle is really loud and seems to have a lot of resonance. Normal light acceleration and driving ok, but as soon as you back off accelerator that resonance is back. Any ideas how to quell this roar as it is quite unbearable inside the car, without having to go to restrictive muff to shut it up.