[willy]

They made changes in every model year, and there were changes within the same year for different models, I/O Sea Drive outboard, equipment packages etc.
It does seem that the changes were all thoughtful improvements rather than change for change sake. So it would seem logical the newer the better as far as addressing shortcomings.
That being said the hull itself did not change so a early vintage if kept up with and with some modifications would be a darn fine boat. The two major changes that addressed problems in the V20's is the filling the hull cavities with flotation after a few years of production and the raising of the floor height somewhere around 1988 or so depending on model. This of course addressed the water draining and coming into the thru hulls on pre floor change boats.
I have had a 1986 and now a 1992, love em both, ride the same, same room and just great boats.