I have the bassni x pipe and cat back. Heat sheilds on the cats were flapping in the wind and I had kind of a buzzing/rattling at very high RPM's. Due to the power I am pushing I was thinking I may have blown apart the inside of the cats and wanted to check things out so pulled them off. For the life of me couldnt get one off without cutting so now its trashed. I put the straight tubes in that came with the kit and the car is loud as hell! Not really any louder when just cruising at 1700-2100 but when you get on the gass, good gawd is it obnoxious. Is anyone else running with no cats? How is the noise level?