Every year is different. A lot of the differences migrated from the SP (the better bike) to the regular Voyageur. Of course, that also means the regular Voyageur was getting better. I would just look at the on line catalogs on the web, and make yourself a cribsheet. At the right (low) price, the Voyageur is a nice bike too.

http://www.trfindley.com/flschwinn_1980_1990/index.html