Mine are in place and functional, but I don't see how they help much. I have an audio panel, nav/com, and transponder. All three have no cooling holes or openings, so the trays are essentially blocked by the sides of the radio stack. I think they may be a source of some of the cool air draft I feel in the winter, so I'm considering removing them and capping the vents.
I think they're just a holdover from the tube radio days!
