I never checked the code, but with the test pipe I got a good amount of power. I had a high-flow cat, but it started to make noise from inside. I was going to buy wideband o2 sensors, get an afc to tune the fuel and adjustable fuel regulator, and also there is a thing called the 02 simulator that tells the computer that the o2 sensors are ok. As for the envirnoment, it is not that serious when compared to tractors or any fucked up car spitting out smoke. My car does not even give off fumes or anything. Thanks for the posts guys.