H_L ,
Jet drives tend to be slower, less efficient than prop drives, unless they are really over powered to start with. So, I would think that using one in a "100 mph" boat is sort of a waste of time, unless you really plan to 'over-do' things - LOL. But then, a "100 mph" model is sort of pushing the envelope anyway, you know? At that speed, how would you keep the intake in the water? That's not a 'joke' question, I honestly can't imagine it...
- 'Doc