Hey guys. I have a 2000 Acura Integra LS and i just ordered a full Greddy EVO2 cat-back exhaust system. I was looking around on ebay and saw replacement cat's and test pipes that were just straight pipes, to take the place of the cat, which holes in them for O2 sensor. Are these worth the 60 bux? it says 10-15 hp gain, even if it was 5, it seems like a good idea to me. My worry is that it will trip my check engine light. Would it work the same if i just knocked everything out of my stock cat? My biggest fear is having a wrong O2 reading and having to deal with a check engine light. PLEASE respond to this ASAP. thanks everyone