What is the best headers for the 05 Sti. I don't really care how much they cost i just want the best performing header out there. I am gettin a Evo2 catback with a helix downpipe if that makes any difference. Thanks ppl.

 

stock headers are the best IMO, the turbos in all the imprezas need all the low end help they can get to spool. An equal turbo equipped EVO will produce a better tq and hp curve because their design is literally inches away from the manifold while we have to deal with the less than efficient distance of the uppipe.

 

lots of Rigoli's cars are utilizing ported stock headers..im sure they have a reason for using them. Cast iron construction is way stronger than any of the aftermarket headers.
From my early experience with cusco headers i noticed more power up the top of the rpm range, but a noticeable 500-600 rpm loss in spool time compared to my ported stock manifolds.
Headers are good for that top end power with the low end sacrifice, ..they could be a better cost alternative for that top end bump than agressive cam swap if anyone had to chose one or the other.

 

while I agree in principle, I have just not seen any appriciable increase in lag using headers on the 2.5, at least not enough to offset their performance gain. Heres a dyno graph of before and after pulls on my car with GT-spec headers, this small section here is the only area where the stock spooled faster, about 100rpms worth right between 2800-3000rpm, theres no way you would even be able to detect that difference without seeing it on a graph, but they were good for +13whp +10wtq untuned and with stock turbo. Header gains only get better with larger turbo and tuning, and headers also help aid knock resistance as well.

 

get the cusco headers. the 4-2-1 set-up should help you from losing the low end. 2 more reasons....it's JDM!!!! and another...all the COOL people have it...hint: our fearless leader *trying to score some brownie points* j/k

 

I've been lookin at the cusco header design. really like the 4-2-1 design. thats what i am goin to go with. thanx for the feedback.

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