Hello,
I apologize if this topis was already discussed throughly, I'm a fairly new member of your community. I drive STi MY02, next year I'm planning to replace the stock exhaust with H&S full de-cat system. To accompany this mod, I'm thinking of intake upgrade and possible ECU re-mapping, to the level of PPP, not more.
So I have some questions:
Air filter - what would you recommend:
- cone filter with heat isolation (eg. K&N)?
- high flow insert in the original filter box?
- full cold intake system (eg. Apexi, K&N Typhoon, APS, etc)?

ECU:
I'm considering two options:
- re-mapping via Ecutek
- piggyback Unichip

What are the pro's and con's, what setup would you recommend, taking into consideration that my plan is to reach the PPP mod level, ie. 300HP/400nM.

Thanks for your help in advance!

I would leave the inlet as it is. This will preserve reliability and refinement.

ECU, exhaust and fuel pump will do what you want.

John, thanks for the answer. What about the Ecutek vs Unichips, which solution would you recommend? And the fuel pump, are you sure that the STI pump needs upgrading?