I need to know how u made it fit.

 

I do...what you need to know?

How I got my cat to mate up to the 2.5" Collector?

 

what is your question....be more specific

you need a 2.5 flange for the cat to match up
if u have a GSR the ehxaust piping is alot longer than an LS/TypeR so therefore you could order a cat custom made from HybridGarge.com they make Carsound highflow cat to fits your needs..............if not simply go to an exhaust shop and shortened your exhaust and get the cat flange simple way just buy the Carsound cat with the flange and shortened to your needs no modificaitons simple bolt on

dunno if this is true for all the GSR but it was true on my 94 and my friends 95 and 97 GSR so ithink its all the GSRs

 

This won't work for a 00-01 GSR b/c the exhaust is the same length as the LS. I'm looking foward to getting a 4-1 header for my 00 GSR, but haven't had time to think about how I would make it fit.

 

damn this seems like alot of trouble just for a header. would still need to do all of that if u had a GSR motor in a 96-00 civic?.

 

Someone correct me if i'm wrong, but if you have a '00 GSR, the DC JDM ITR header will bolt up fine. Exhaust components for the LS, ITR, and '00-'01 GSR are the same

 

No, the collector on the header is 2.5", and I believe my cat is only 2.25" big. I'm not worried about the length, just the connection.

 

oh, I thought you we're talking about length, sorry. but yea u need to bolt the collector to a 2.5" cat or some kind of reducer.