Differences between model years are minor, including color combinations, upper j-arms on early models (1987 to 1990) followed by a-arms on subsequent models, the addition of a brake light in late production machines (2002 and on), and minor differences in electrical connector styles. So that knocks your question of what years to stay away from since there weren't that much changed. We don't know how much money you want to spend on this thing, what it's gonna have when you buy it etc so it's hard to answer your question right now. Usually when i get a bike i bring it straight to the garage and start ripping shit off of it. First is the parking brake block off get rid of it and get a blockoff plate, then take the TORS (Throttle Override System) off and get a TORS eliminator kit, shave the front fenders, order pipes, vforce reeds and so on and so on. Just do some searching on here you'll find out more information just reading than anything else.