I looked at and visited several Ericson 35-3s as well as a 32-3 and and some Ericson 38s (original layout). All three were great boats. Beyond the dedicated shower in the 35-3 (and 38), there are subtle differences in additional storage and the feeling of space. The Ericson 35-3 is also a bit faster (PHRF 123 vs 156). I ended up with a 1987 Ericson 35-3, which is the right size for us. With each increase, the extra length and beam is noticeable and there are more drawers and cabinets. The v-berth and settees are pretty similar in size - the differences appear elsewhere. A few extra inches in the galley, some extra inches in the cockpit, etc. I think the engine access is the best in the 32-3.
I have the Universal M25XP in my boat, 23 hp vs 21 hp, which was new for the 1987 model year. It leverages my basic 2-blade fixed prop to produce a speed of about 6.5 knots. If you scale back to about 6 knots, it uses only 0.4 gallons per hour.
My surveyor said that about 80% of boats this age have elevated deck moisture and about 20% have soft, spongy decks. I am working on rebedding everything to prevent moisture intrusion. Key problem areas are the anchor locker, dorade vents, and surrounding areas. Solution to wet decks is to replace the core, either from above (very difficult/impossible to seamlessly match the original non-skid) or from below (tear up headliner and work against gravity, messy, work around bulkheads). If I need to do anything, it will be from below as my non-skid is still in excellent shape and resurfacing the entire deck can be very expensive.
Example of resurfacing deck after core replacement (in this case, the entire deck):
Example of core replacement from below (much smaller area to replace):
Hope this helps! I don't think you can go wrong with either choice.
Dave