Ok heres the deal. I have a 2001 GS-R. The only exhaust mod that I have right now is a Greddy Evolution(2.36in). I just bought a OEM JDM Header. And am currently shopping for a Carsound cat. Ok here is my question. Is it worth getting rid of my greddy for a custom 2.5 in cat back? Becaue I notice a lot of you ITR owners who have JDM Headers and 2.5in IN/OUT carsound cats use 2.36in exhausts(Apex'i N1 for example). Will I benefit much if I continued the 2.5in exhaust all the way through. My future plans are a full JUN top end, shooting for 180+whp. I also had the idea of just getting a 2.5 in IN/OUT carsound cat(94066) and haveing a 2.5inch flange put onto my greddy. This way later on in the future I could always goto a 2.5in exhaust without having to get a new cat. VS. getting a 2.5in IN/2.36 OUT cat and being limited. I hope what I said made sense. Thanks.

And SMSP if your reading this, please check PM's

 

Please?!

 

You're thinking about this entirely too hard. Get the JDM header/2.5" Carsound, and bolt it up to your Greddy. It's not going to hurt anything to have a 2.5" Carsound bolt up to a 2.36" Greddy exhaust. If/when you decide to upgrade your exhaust, you'll be able to use the same cat. Hope that's the info you were looking for.

 

Oh, I was under the impression that the 2.5in flange would not bolt up to a 2.36 flange. Call me a newbie I guess.

Also would there be any point in switching out my greddy for a n1? Besides being louder.

 

No there isn't. Stick with what you have.

 

i guess what i REALLY REALLY want to know is if the 2.5in cat outlet flange will bolt to the 2.36 greddy flange

will paypal $.50 to whoever answers this question

and for god sakes SMSP answer your PM's

 

Yes it will bolt up. And you dont need to pay me.

 

Not everyone is on H-T 24/7, especially not on holiday weekends. Be patient, I'm sure he'll answer your IM when he gets it.

As someone else already told you, the cat will bolt to the exhaust just fine.

 

just a quick question, how long does SMSP take to make and ship a header, from a previous thread that i just read, seems like 2 weeks?

i know i should ask SMSP but hes not around right now

 

Your GReddy EVO will be more than enough for the JDM header and 2.5" cat. The APEXi N1 is not a 2.5" exhaust. It's 60 mm piping (2.36") just like your GReddy EVO and most other aftermarket exhausts.. Stick with it.. Good luck..