i found the time today to pull out my whole exhaust and take out the cat and the stock silencer. Before i did it, ran the car without the axle back, i.e. no resonator and muffler. it sounds MEAN! my bros friends were in the house and they came out wondering what that sound was. IT IS LOUD AND DEEP! I think every GTS owner should at least unbolt it just for fun and see how its like. Im glad it did. I didnt get to do a test run since there were cars parked behind me. It would be too scared anyways, just revving it was insane, and i only took it to 4k. Imgaine lift! Anyways, the exhaust is back on now, and at idle, the air flowing out of the muffler is 5x more than what it was stock w/ the HKS. It much louder and still has that deep tone. Im happy i did this instead of gutting the resonator. Bad side: No cat, so you can smell the exhuast gas alot.