I had a vt with a redback 2.5" cat back exhaust it was a auto and the drone pissed me off no end but with me xrt ute next to no drone and a rumble at the back to be proud of... all I did was replace the middle muffler with straight through pipes but its now been a little while and I want a more crisp sound than what the stock rear puts out... but after reading these posts I wanna change the cat out now too