Hawk welcome aboard.
The SD had an options for thrusters one at the bow and two at the stern (each coner). This was a custom design that is no longer made.
BTY this system has it own batteriers
1. I believe the best option is to have te motors rebuilt if possible, this can be done by a local shop that works on motors such as starters.
2. Use yachtworld.com to look at prices listed for this model. Rember list and sell are two different things.
3. Sound hull, good seats, gel coat not cracked too much, all switches working, head should flush, clean bilge, no water in O/D gear lube, engine oil clean, engine runs good and no over heating at planing speed, ....
4. Depends if you feel you know what to look for else spend the ~$300, however i would be most concerned about the engineand drive and a surveyor does little here unless they are trained to do so or just hire someone who does nothing but check these systems.
lets us know how it goes and which one you decide on.
1997 2400 SCR
5.7 Vortec / Bravo 2