Posted this over in the Hybrid section but didnt get a reply. Also searched already. If I went with a 2.5 in/out cat would they have any problems welding to a LS stock header and a stock civic ex exhaust? Or do I have to get a header with a 2.5 collector and a 2.5 exhaust? The car is a 96 civic coupe with a GSR.

 

just do the 2.5in collector mod, it better anyway or jus buy an itr header an get 2.5 exhaust

 

They shouldnt have a problem welding it on. Plenty of people go 2.5" from the cat back. Just make sure to get a 13" cat and also depends on if your OBDI or OBDII if you need an o2 bung.

IM me if you need more help