I have an 05 Z with headers, Borla cat back, Injen CAI, Plenum spacer, ACT clutch, Fidanza flywheel and unichip. My question is should I leave the stock cats on, or should I put test pipes on? How will this effect my performance?

 

Please refer to this thread. https://my350z.com/forum/intake-exhaust/261870-intake-exhaust-rules-faq-you-must-read-before-posting-updated-5-21-07-a.html

 

I don't think that the above link pertains to my question. I'm asking if adding test pipes to my car which has headers and a cat back exhaust is a good or bad idea. Will this cause in general a loss of low end torque or will it improve my overall power curve? I have searched around on this site and have not found this question.

 

IMO, you'll only gain power across your whole RPM range...that's how restrictive cats are. but, you have to deal w/ emissions, smell, rasp, and a much louder exhaust...

 

get high flow cats

 

Performance? Go for test pipes.

 

i have a set of high flow cats up for sale if interested pm me
they are R/T high flows

 

A good set a HFCs will perform just as well as test pipes.