I think unfortunately you're dealing with something made by Heater Craft, not by Supra. I have the exact same part in my 1989 boat (retrofitted) and yeah, it's finicky. Mine's been stepped on a few times and it has a very hard time going back in. Sadly, I'm not aware of any upgraded version. What you could do is replace one (or both) with just a straight vent. Then you just drape a towel or blanket over your lap and still get a lot of heat that way... unless you're trying to get heat to go far away from that point, a straight vent will crank out a good blast of hot air. I have the tube in my boat to reach the back seat, and only take it out when absolutely necessary.