Originally Posted by flinchy
that thread is to do with testin POORLY DESIGNED headers... if you read the whole thing.
look at other tests, they show that headers are a major improvement, especially with forced induction.
Headers historically produce big power for 2 reasons
1-OE was a simple manifold/dump system
2-headers (or manifold even worse) had primary cats built in
Either scenario replacing these by a tuned set of regular headers would yield big gains.
Taking a set of OEM headers with no cats leaves no room to be gained on the stock engine. Add 150hp then I am sure there is room for improvement.