im looking to swap my up-pipe over after JGM said this could be the reason im running 300 bhp instead of 320 bhp with all the mods i have. At the moment i have a japspeed up-pipe which im told isnt the best although i dont know what size it is ive been told its more than likely oversized and this will lose me power.....so what im going to do is swap it over and get racedynamix to tweak the map i already have.So what im asking is which is the best up-pipe i can buy ???????? maybe a STI one??? or is there even better pipes out there which will improve my power. my car is a bug eye wrx 2002.

 

Speak to Alyn at AS Performance about a Harvey up pipe.

 

At that power standard be fine if not better that what you have. Them up pipe as Si said there pretty big bore that's not needed and you will lose spool for sure. As ditch said Harvey smith up pipe the one you want from alyn at as performance.
Stick standard headers and up pipe back on return to Si Jgm

 

i think i already have standard headers on !!! as it wasnt in list of mods when i bought car..........so just swap the up-pipe with a harvey smith pipe and go back to tweak map is what we are saying??? any idea how much the up-pipe is roughly??

 

As said, speak to Alyn at AS Performance. He'll know how much they are (obviously)

 

£145 if not fit a standard one be better than a 5inch bore up pipe lol