I just bought the si because my gsr was stolen. I am looking for the best power gains. is 2.5'' piping the best for my 1.6l or 2.25''. i have about 700 dollars to spend. what is the best i could get fro around that price range and what inch piping.

 

2.5 cat back made my own with mandrel bend piping for $100

 

2.25" Apexi n1

 

get a WS2 and you will only spend half your money and then you can buy something else also and its 2.25 piping and sounds good not to loud or ricey

 

$700 bucks huh? I say jdm ITR header and any old 2.25" piping from your local muffler shop, as for the muffler, I would suggest an es oval muffler, its only 100 dollars and is a great piece for the price.

 

Import Tuner Magazine did some mods to a b16 and the apex n1 yeilded reasonable power. This is towards the end where they do dynos after each install

 

greddy evo2 or evo

 

on my '00 ex, i just did 2.25" Thermal R&D Classic Cat-back (stainless).. awesome man, i must recommend.