When I put in my header my car got really whiney(ricey). I hated the raspy sound. I already had intake, exhaust and testpipe. I read that you lose that sound by putting the cat back in. I definately lost the sound, butt performance to. The car lost alot of throttle response and just doesn't pull as hard. And yes, I did reset my ECU. When I first put it in it didn't make that much of a difference, but with the header it makes a big difference. In short, the crappy sound is worth the power.

 

its all relative to your current setup. i know on a turbo setup itll give about 10 hp to the wheels. but thats a turbo. i think your better off going hi-flow cat even with a full catback and if you have the money a downpipe.. open up the TB and IM, and your car will sound awesome.

 

Yeah, but I'm up for inspection and I doubt the place I go to will look for the first cat. Right now all my money is going into my supercharger.