that's really weird man. i can't see it being because of the intake. i mean, the vehicle has "virtually" no idea anything has change. it's probably cause the change in pitch/whisling noise you may be noticing.
if you're really curious, and are pretty handy, there are walk-throughs on how to install an mds light that comes on when mds kicks in...not only is that cool, you may be able to find a correlation in the noise you hear and when that mds light comes on.