My 340Da when slowing down to an idle from plane will throw an alarm and go into limp mode. Oil pressure is good when this happens. If you slow down below 1k rpm for a few seconds it will be fine. I'm thinking oil pressure switch not oil sender switch is the problem.
Last summer we moved up to a 2001 340 our 310 was easy to see things that we changed the. 340 not so much. Started with the electronic Garmin 1042xsv with radar.
I would think you are responsible for everyone around you if an accident would happen. You can't be sure someone else wouldn't be affected by you running your generator.
Depends who you talk to but yes they will help with lower rpm for planning speeds and increase speed at a lower rpm plus help give you more thrust when docking. How much of a difference I doubt if it's huge but over time it will be a savings.