O/B Question

[Luna Sea 3]

I am looking to get into something more comfortable for next season. I have been looking and found boats in the late 1980's, 31' - 33' size, Flybridge, with twin I/B.

I never owned an I/B, so my question is, what is the difference in the fuel economy, winterization, cost to run, and maintenance compared to my present power of twin 175's O/B.

Also, how does the shore power work. Is it as simply as plugging it in and everything on your boat now has power.

Haveing a boat that size will be a new experience for me and debating to see if it is worth it. I am trading off speed for comfort as I am getting older.