I have a 2003 touring 6speed. As of now i have a injen cold air intake and nismo cat back. I ordered the strup headers and the 5/16 intake spacer.

My question is, is it a waste to put on the headers and leave the stock cats? Should I put resonated test pipes on it? See I don't want it to loud and I love how it sounds right now!! what do I do??

 

Performance: Headers with add both horsepower and torque regardless of what you do with the OEM catalytic converters.

Exhaust noise: Replacing the OEM exhaust manifolds with headers will improve exhaust flow. Greater exhaust flow means more noise from the exhaust system. There is no way to get around it.

 

do these cars sound good with headers and nismo cat back??

 

The NISMO exhaust will still maintain its signature sound it will just be a bit more loud.

 

if you dont want it to be too loud, you have no other choice then to leave the stock cat's on. I have heard of trying to gut the stock cats, because it would increase flow, but still not be all that loud. I wouldnt do it but thought i'd throw it out there.

 

you never want to gut the cats, it's like a bubble in the exhaust system and will disrupt laminar flow of exhaust gases and have a negative effect on scavenging. Btw, i disagree with what was said above about headers. If you are going to increase flow above the cats then it only makes sense to increase flow through the entire system, otherwise any benefit you wish to reap will be negated since the stock cats are known to be the choke point our exhausts. I would invest in some nice high flow cats or test pipes with the cel trick if your area does not have emissions testing.

 

Ok I ordered resonated test pipes. They shouldn't be raspy should they? I mean how loud is it going to be?? it is pretty quiet now!

 

what kind did u order?