I looked at the ARP unit. Kind of interesting but at least in my case I don't believe it's a needed $135 buck addition. For one thing, contrary to their claim that the snap disc thermostat is installed over the boiler flue exit on that side of the condenser, it's not. Dometic recommends the instillation be on the outboard cooling fin OPPOSITE the boiler, exactly where mine is installed, not over the flue exit and their 2 fan option puts one fan at the bottom of the rear cavity. My opinion (opinion only) is that multiple fans in the upper cavity exhausting through the upper vent pulls ambient air over the entire refrigeration unit anyway.
I do agree with their premise that the addition of an internal (in the fridge section of the internal cavity will go a long way toward cold air circulation inside and eliminate the stratified air in the fridge which will allow for faster cool down and better (more even) interior temps. Easy addition connecting to the interior light. In fact, I bought a small muffin fan just for that modification