I am going to order a JDM ITR 4-1 header for my B16a2, i was wondering what is a better setup. To get a test pipe or high flow cat. I am currently running a 2.25 cat back Tanabe Super Racing Medallion exhaust w/ stock exhaust manifold and cat.

 

Unless you have a very built motor, just run a stock cat. Almost every aftermarket cat I've dealt with is completely destoryed within a year and a test pipe is a bad idea. I know, I'm stuck with one for the time being. They make your car louder, smell bad, and if you get caught it's a HUGE fine.

 

There was a thread a few days ago comparing the test pipe and the high flow cat and they said both are very similar in performance. But don't quote me on that.