testpipe?

I've heard the word testpipe now a few times and about them being used on integras. What is it, where does it go, and how does it work. What can you expect from it and what's the cost. Sorry if this is a stupid question I just haven't heard of it before.

Test pipes are just straight open pieces of exhaust pipe to go in place of your catalytic converter. They are illegal for street useage.

Check out the search feature on this site - I'm sure there are many test pipe threads

well i'm about to put on a focuz high flow cat. Shouldn' that make about the same difference in performance ?