Why are you revving the engine up to 3,000RPM??? even merging in to traffic on the freeway it's rare to need to rev the engine up that high.
#4 is the tube I'm talking about and most part stores do not sell it, a Honda dealer might charge you $15 for it or
Honda Automotive Parts sell it for $7 and a few bucks for shipping, if you order that tube get part #3 as well, you can not get to that tube by jacking the car up, you need to find someone with small hands, to get the grommet (#3) out you need needle nose vise grips.
A cold air intake will let you hear the engine more because it will de-tune the air intake and make the engine louder/rougher/rattle, I don't know of any positive effects that it could have.