Capped off side return, moved filter rack to top of furnace and connected plenum into return trunk. Capped off return drop. Re-situated flex duct that was kinked over the boards above furnace and strapped it to the bottom of the boards to remove the harsh bend. Added insulation to return drop and plenum. Added insulation to supply plenum. Moved exhaust vent to exit furnace from the side rather than the top to allow for filter and blower access. Re-affirmed airflow and refrigerant charge. Added a few ounces to achieve 12° subcooling.