Nizpro Marine created this 633-horsepower supercharged monster, and You all need to check this out because I am blown away. They focus on upgrades and modifications to Yamaha outboards and they developed the superchargers for those engines entirely in-house. The engineering involved is phenomenal. Here's the description of the 633R from their YouTube page:

Nizpro Marine has developed the worlds most powerful outboard.

You start with Yamaha’s brilliant, and dare we say venerable 4.2l V6. You add a custom plenum (hence the red alien), separate, additional raw water cooling, and Eaton’s R1900 supercharger on top. Yet the really brilliant effort is in the re-map of the factory brain.


Now the 633RR adds a bigger pulley, new injectors, forged pistons, new valve springs, ported heads, and billet conrods, then some other more incidental bits too like throttle body and injectors, as well as a new drive leg. All very cool stuff, and the reason the whole thing is as bullet proof as the standard 300hp from Yamaha.