Ok Just an update, I got a Bosch Universal 4 wire O2 sensor for cheap and it works great, but one thing sucks, I replaced it and found out that when I had the bad O2 sensor in there, I think it made my car run bad but I couldnt tell, I know there is a difference because I get about 80 more miles to a tank of gas....:-).

If the O2 sensor was not working the way it should can that cause my CAT to build up crap and clog? Because I just moved to Bellingham and out here there are no emmissions tests, so I could just take it off, but in a way I dont want to....

Should I save and get a high flow cat, or just take it off and run a straight pipe?