Any one done it? Do you have to cut the cats off or are they bolt on. Any one know what a test pipe is. I got a 2000 Avant A6 w/CEL. I dont have emmissions where I live and want to remove the CEL. Any Ideas except forking out the 1400 to get the cats replaced by a shop? I Already got the parts required by the DIY post about Testpipe CEL.