Originally Posted by Celery GT-5
The "bumper side covers" as subaru calls them, have a vent..not sure if that has any function. They are a real bitch to take off and get back on properly
I think those covers can only really vent air from inside the bumper. I'm not sure if they do much. The one of the driver's side may actually be sucking in air if you have a cold air intake.
Once you get used to it, they're really easy to get in and out. I take my driver's side one off and on all the time. Only takes a second or two to pop on or off.