Screw Air boxes... I would get the Velocity Intake if I were you.. For a little over a hundred bucks, you can cut out the air box, and have a cold air intake like setup that will get more air into the motor than any other set up out there..
Well in that case, what I would do is either get the GYTR Filter set-up with the pre filter, or get the other velocity intake, which is just a different, more free flowing filter mount with a K&N and a pre filter. I would also recommend either Uni Air Vents for the airbox lid, or the EHS Racing lid..
CFM makes completely different air boxes, made of aluminum, but i'm not sure how much better they are and if they get any more flow than the original factory air box.