Ok currently I have a 94-99 GSR DC Sports 4-1 header with crappy 2" collector and a test pipe that's 16.5" long.

I want to upgrade to a better header with a 2.5" collector and also upgrade the test pipe, anyone know which one I should get??

Looking into a JDM ITR one but I'm not sure which test pipe I would need, thanks.

Here's my current setup:

 

Best thing would be get one of those adjustible test pipes if you dont want to go to a muffler shop.

 

I didn't even think about that, good idea thanks man.