when people refer to the test pipe, is that the downpipe?

 

No that goes in place of the catalytic converter. Its called a test pipe because its illegal to remove the catalytic converter. The "test pipe" is a weak loophole used to diagnose wheter a plugged cat is causing issues with the vehicle.

 

i was way off, damn. So does the test pipe allow more air flow (more hp), and would it pass an emissions test?

 

It will give you a few more ponies. I have heard that yes you will be able to still pass emissions and no you wont. I would give it a shot though. If you dont pass there is no penalty, you just have to go home and put your cat back on. Then retest. If you pass WooHoo! Im planning on putting one on my car in the near future.

 

Your car wont pass emisions without a cat. Not having a cat will also turn your check engine light on. Not really worth the insignificant hp increase you may see.