Originally Posted by 1speedbike
Nobody really can. It might help push just a little more air up into your intake snorkel at higher speeds, but really they're for looks. Especially if you powder coat them a cool color so they're more noticeable behind your grilles. It has the same effect on performance that a carbon diffuser does for weight savings.... almost none at all.
^this. Though im a sucker for Red scoops behind matte black grillles.