The best of all intakes seems to be a dc2 airbox with a spoon filter and a cold air feed. I personally have a tegiwa slug (copy of the j's) its a good upgrade over standard and has a very loud induction noise and im sure has some gains but wouldnt be as good as dc2 airbox imo. In trackday conditions id imagine the slug would also suffer from heat soak due to the design of the intake itself. It does sound great in vtec though!
what all is done to your car?
an inlet manifold isnt one of the first mods id be doing,either is a throttle body,
a good closed filter intake with a cold air feed directed to it, a 4-2-1 manifold,2.5" decat and catback, try and stick with good brands! a bigger tb and intake mani are a bit of a waste of money considering the gains you,ll get from them!