yah I have seen a few people say, oh well it needs a mod so i guess I wont do it, to me this really doesnt make sense.
I mean you are going through installing on of the bigger bolt on mods you can do, also one of if not the most important for our cars and dont wanna take the extra 5 minutes and 20bux to wire in a MIL fix?
Im sorry but if you want anywhere near decent gains you need to go turbo or get that damn primary cat out of there, which can only be done with a header.
Also if you can wait a while, wait till december, get the ractive header and their new catback system at the same time which will require no mods since their catback will have the 02 sensor in place from the factory. plug and play except maybe lengthening the 02 sensor tube a little.
for the price/quality/gains i cant see anyone beating this header right now.