I had originally planned for a custom twin turbo, then switched to a supercharger (to preserve exhaust noise), and now I'm thinking about the Jenvey's too.
But if I did the Jenvey's I would have to have some additional kind of HP booster. I've never had ITB's before, but I've done direct port nitrous in various intake manifolds in the past.
Have you considered this? Another 150HP would be fun for brief stints!
It looks tight, but a fogger nozzle may be able to be inserted in a runner downstream of the fuel injector (brief research has shown this to be OK). Or, a fogger nozzle could be placed in the bellmouth, but this wouldn't be as efficient for the nitrous path.
Just a thought....
Dave