Like VTEC said, you want to shoot for air velocity. Remember back to your physics classes where PV=nRT, basically pressure and volume are inversely proportional. Air flow in itself does not hurt performance but if you increase the port volume that the air has to travel through and don't increase the pressure moving the air through that port, then the velocity will decrease. So what we try to do is to make the port shape more efficient so we don't have to remove a lot of material and decrease velocity. Ideally a port would be smaller than stock but flow much more air and that would make more torque and HP. That is basically what a supercharger or N2O does, move more oxygen in without increasing the port volume.