I really like the comparatively simple installation, and have also been looking at them for other projects. Seems like it could be undersized or under driven to provide increased manifold pressure, without blowing up the motor at full RPM.Look at procharger. I live at 6000 feet, and ran into issues with my gutless 4runner barely being able to pull a 3500 lb trailer up a 2000 ft mountain pass. My hp jumped to just under 500 hp and I doubled my gas mileage. I know that procharger makes superchagers for marine purposes. I know apples and oranges, but worth a look. I know propping also makes a big difference. Both pf my boats are propped at 13 with my average elevation at 7500 ft.
Edit: I drove a toyota with the 22R motor for years, if you run it above 5000rpm they do pretty well. I drove that way for over 100k and gave the truck with 200k to a guy who got yet another 100k out of it. I bet a super on one would be amazing.