How old is that Olson 30? 30 years? 35? If something was built badly and was going to break, don't you think it would have done so, already? That doesn't mean that you shouldn't look over things carefully, but if a couple of boat repair pros say "it's fine" then....
Regarding the electronics...you should do what makes you happy. If muddling with computers and signals and whatnot makes you happy, then you should do what makes you happy. But if it were me and I couldn't sail the boat, yet, I would go over all the rigging. Instead of paying money for more electronic widgets right now, I might replace some running rigging. I would take the sails off and lay them out on the grass (when it's not an absolute deluge from the sky) and inspect them. I would take the sails that needed some work to a sailmaker. I would fire up the outboard and putt-putt around the harbor a little bit to make sure that it works and pee's out cooling water. If it was a 4-cycle and I didn't know when it had last been serviced, I might take it home and do that...or give it to someone who can service it. I"d make sure the VHF radio works. If there's an autopilot, I'd make sure that works, and will steer the boat in a straight line while putt-putting around the lower harbor.
But that's just me. You should do what makes you happy.
1968 Selmer Series 9 B-flat and A clarinets
1962 Buesher "Aristocrat" tenor saxophone
Piper One Design 24, Hull #35; "Alpha"