:or QuietCar sound deadening material. I've used the Whisper Mat and it is somewhat effective at certain rpms. QuietCar is billed as even better and is applied with a brush or spray can, however I've never used it. :Both methods will require a bit of your time to install. Cats and/or the resonator will cause the most reduction in sound (a little horsepower too ;)), but with a 2.75" system you're still going to have some noise. Add the cats first - it's make your car legal for street driving - and then see how it sounds. If still too loud, add the resonator, then the sound deadening. Good luck.
Hey maybe a pic of my system and you could tell me if cat will work?