Does anyone have a trick on how to remove the heater plenum with the heater box still in the car? I can't seem to get to the back screw on the bottom to remove the plastic one and replace it with a correct cardboard plenum. I don't really want to move the heater box away from the firewall with fear of scratching something, plus I have the AC unit in the way along with the console. As much as I would love to replace it with the correct one, I don't know if it is worth the aggravation and potential to damage something else for just one point on the judging sheet