RD..
There's an chat somewhere about removing the cat in the 2-1-2 that will cause the 02 sensors to misread making the tune next to impossible to control at low and mid range cruising. I think it is in the tech talk com site and was discussed by S. Cole... guessing on the location but pretty sure. Said something about having to move the sensors up a few inches towards the heads to get a decent reading. Anyone else see that thread?
Actually, prior to them developing the "x-pipe", Fulsac would remove, and probably still will, the cat for you if you send the pipes to them. I think they do it for around $175. Steve at Fulsac, had pretty good luck tuning them and getting some basemaps for the TTS Mastertune. Obviously, his new x-pipes are better than removing the cat, but it's still an option. He originally was concerned about the O2 sensors being too close together that there might be cross-talk issues once the cat was removed, but he found out that there is enough pipe, from the front header I believe, that continues into the collector more than the rear pipe does, that it didn't produce the O2 sensor issues that he was orginally concerned about. There a thread on here in the Exhaust section that explains it all.