Nice boat. I have logged around 2500 hours on a similar boat. I highly recommend them for boaters:
1. Spend a ton of days on the water (racking the wear, tear, an even enjoying your performance boat not practical.)
2. Allows you to actually get other purpose boats that you exactly want.
3. If you have small kids or are entertaining - you will be able to relax knowing they could not even light the thing on fire and effect your program
4. You will always be able to sell for what you have into it.

On to the motor:
1. In my case I have a 140 Tohatsu (Nissan) it has been bullet proof
2. Top speed maybe low 30 - depending on load. Speed should not be your concern - keeping the surface temperature of the pole below atomic hot would be priority 1.
3. I would repower to a new gen 4 stroke for the fuel efficiency
4. Unless you do the work and rig yourself you will be hard pressed to find someone who will mount something that big on a transom not rated for weight / HP. As others have said it is not like you will be doing 50 + in this thing ever

Enjoy!!!