On the 1st Gen. X's, I know, that where the air came in was from behind the grill. And the tube has a square box covering it that has large oval slots on the sides of the box. The box was held in with some of those plastic push pins, that I cut off and pulled the whole thing off. But like Sk1er said, there is only a small hole in the newer boxes that has like a trumpet end on it where the air comes through. Even if you were to pull that out, the opening is still about the same size. But if you were to cut open that side of the box it open it up to a lot more air. Or there is always a KKM if you'd want to replace the whole thing. I've also heard that in some cars, after the MAF, somewhere in the tube that goes to the intake manifold has a restrictive plastic piece in there. But I can't be certain about that.
