So i was wondering about the header and exhaust piping. I was researching exhausts and they showed different widths of piping of 2.25, 2.5 etc. I was wondering how i could check the header piping that connects. While i was searching headers i couldnt find a diameter measurment so i was wondering if there was something i was missing.

 

generally you just have to know.
stock is something like 2.0" I think, dont quote me cause I'm not exactly sure
gc sports are 2.25. as are usdm itr(I believe)
jdm itr are 2.5


what size exhaust are you looking to get?
If you're not planning to go forced induction, 2.5" should be about the biggest you'd need.
Put in a 2.5" high flow cat as well.

 

so i was thinking about getting the greddy evo2 exhaust and a dc 4-2-1 ceramic header both made for my car so they should have the right sized piping for both products right?