exaust 2 " or 2 1/2"???

i have a 92 prelude si and i have headers that are already on it buy i just got a feeer flow cat and now i am getting all ne exaust piping so i was wondering which whould get more hp gains 2" or 2 1/4" piping??

n/a or fi? i would go right in between at 2.25". 2.5" is a little large for most applications, particularly if you're staying n/a. you'll just end up losing too much low end. make sure you get consistent diameter throughout the whole exhaust from the header collector, through the cat, through the piping and also the muffler.