or lets say you've got a stock gts. you add trd Intake, exhaust, and headers. how much power you got?
there is only ONE exhaust manifold on the celica, hence we have One headder.
if we had a v4(boxter style) v6 or v8 we would have 2 exhaust manifolds hence "headders"
trial headder has been shown to run pretty lean on a dyno, as well as other i/h/e gts's which will make more power,
stock dynos are anywhere from high 150's to low 160's and i/h/e gts usually dyno in the 170's
gains from i/h/e are in the 10whp range.
as mike said add the pfc and it gets multiplied. as we will soon see with my car