I don't think the DC header has EVER made a difference, but maybe I'm just biased against a $300 header that looks identical to the stock unit and makes no more horsepower. *shrugs*
V-AFC or E-manage alone will do nothing for now until you hit the dyno. Depending on your power levels, A/F mixtures, and budget, you'll have to decide the next step. Until that point, hold off on any electronic or fuel-related mods. Like schwett said, make it a priority to hit a wideband o2-equipped dyno ASAP.
Then afterwards you could install a Kami header and do a back-to-back dyno comparison for the rest of us (unless Prelude_LC beats you to it) and finally let us attribute something to this damn piece instead of mere speculation.
