I have a 93 civic with a jdm b16 in it. I was going to order an omni test pipe for it. I was wondering is the 2.5" flang only on type r headers. And all of the other ones have 2.25 flanges. When I went to order there are two options jdm 2.5" or usdm 2.25". Which one should I get? I think mine is a 2.25 right now but I just wanted to make sure since it is jdm.

 

If you got a stock B16 header than get the USDM

 

get the USDM 2.25 since your running a stock jdm b16 header