other than engine and all electronics replacement, what are the pit fall
to
look for.

"Other than" the electrical and engines? Yeesh, how much of a headache are
you prepared to put up with, scratch that, PAY FOR?

It's one thing to have a boat that's taken on water for a few hours.
Totally immersed for a period of days is a whole other issue. Water gets
into everything. Depending on the boat's construction, the type of water
and the duration the list of things damaged could vary widely.

But without better detail it's pointless to describe all the possible
problems. What sort of boat are you talking about? A 14' aluminum bass
boat? Or a 50' wood hulled aft cabin yacht?