On the nitrous thing. When my dad raced boats. (Unlimited off shore) he ran a mercury 2.5l black max. Nitro, alcohol, nitrous system. Only way to deliver the nitrous was direct injection ports. The alcohol was also direct injected. The engine work was performed by a guy named Chucky Goodman. Think he was from Alabama. Biggest problem we had was after we came off full throttle the engine would want to seize up. Had to add a secondary oil injection system and a timer to up the oil when running the nitrous. And still the engine didn't last more then a few races. It was crazy fast though.