I am thinking about taking out the test pipe and putting the OEM cat on. Am I going to lose power with this??

The test pipe makes the car very loud I can't stand it sometimes.

 

The short answer is yes. Most of the gains you see stated for aftermarket exhausts have a lot more to do w/ the test pipe than w/ the exhaust itself.

 

I have the Megan Racing test pipe and it has a small resonator built into it and I didn't notice any difference at all in the volume of my exhaust after it was installed.

What are the rest of your exhaust components? Header?

 

Oops, needed to read your sig. Yeah, that T1R 70mm is loud and nasty.

 

You will lose some power and a re-tune should follow.

 

go to www.myspace.com/spoonsports2k and you can hear my full exhust sys. megan headers,megan textpipe, and apexi N1 now that's loud lol