[Richbot]

300cell - this is what differentiates this pipe from the others - it uses a more restrictive cat than almost every other HFC-equipped xpipe on the market. The fit isn't great but the price is relatively reasonable and with these cats it's the only one I know of that has reliably kept the CEL off without O2 extenders or other defeat devices. It probably makes 5-10 fewer hp across the range as a result of using a denser catalyst brick.

I have an Evolve Stage 1 tune, which has been on the car for more than 100,000 miles. secondary O2 monitors are active and were intentionally left on - it's the same exact tune I used when I had the stock xpipe on the car.

Also, it may help that I had evolve leave the cold start sequence intact with this tune. Shutting it off causes the cats to light off more slowly, from what I understand, but I'm not sure at what point the car will throw an out of range code, if it will even do it during the first couple minutes of driving or if it doesn't matter so long as it's in-range when the car is warm during the driving sequences it uses to monitor.