OK..I spent a few minutes in the back seat, with the car in the garage this afternoon...tapping on the rear shelf, seems to produce the same rattle/vibration I get while driving, or with high bass on the audio system. It just seems to be loosly attached...or perhaps, not insulated underneath...Anyone have any experience in removing this plastic shelf and battery vent panel???

(gotta love Tucson in the winter! 80 degrees last few days..but we pay for our mild winters in the summer!)

Thanks