I am the fifth owner of my 37 year old boat. Many improvements were added before me likely the ZF controls being the most valued? I love them!
I have continued up grades with some passion. Big ones are a new genset, hardtop over cockpit with enclosure, solar panels, auto pilot, all new electronics, water maker, increase storage via cutting hatches into floor and transom, curtains, upholstery and new flooring throughout, BRNCL security system, modern ice maker along with dozens of minor upgrades. Last but not least Eartec (marriage savers).
All of these improvements were worth the money but if I had not done any of them but were thinking of which I would do first would be the auto-pilot, water maker & Eartec head sets. They all made the five months of cruising we do the the Pacific North West much more pleasurable.