I love my tsp duals. They sound amazing with the cam, but the interior resonance is very annoying. I think its mostly due to the mounting of the exhaust hanger bracket to the floorboard. Im thinking of putting some rubber hose inbetween the bracket and floorboard to cut down on the vibration. Anyone tried this? Im also planning to put some sound deadening throughout the car this winter.

 

So is it the vibration or the sound that is bothering you? If it is the vibration, you can add some rubber in between the mount and the car like you said. If it is the interior sound, then I would highly suggest getting them ran out the back. On my previous ls1 I had TSP true duals and a cam and the interior sound was too much for me. I tried adding the sound deadener but it didn't do much. Once the exhaust was ran out the back, it was 10x quieter inside the car.

 

Its the "wawa" resonance sound that drives me nuts. Id love to run it out the back of the car, but I really dont like the look of exhaust tips on the formula. Oh well, I will give the rubber mount a try and see if I see an improvement.