One thing to note about these headers is if you live in a state that has strict smog laws, these headers will cause your car to fail smog. This is because the o2 sensor on the front bank header is only monitoring one cylinder rather than all 3, so the ECU thinks the car is running lean so it adds more fuel... the result is failed smog and you end up burning more gas. I tried this with OEM cats / Random Tech cats & Prospeed cats... nothing made a difference until I replaced the headers.
After dealing with this issue myself and banging my head against the wall trying to figure out what the issue was, I bought CT headers and saw the o2 sensor was at the collector not on one of the runners, the car passed smog with flying colors.... going the cheap way out will usually bite you in the ass in the end.