1988 thru 1990 = 62-series - leaf sprung, automatic, injected
1991-1992 = early 80-series - coil sprung, automatic, injected
1993-1997 = later 80-series - coil sprung, automatic, improved motor, possible factory diff locks.
Spend some search time in the Tech forums, lots of these things have been hashed thru....WHAT you are going to use the rig for is a determining factor....IMO, the kewlness is highest in the 62-series....
I've got a 1996 80-series and really enjoy it, primarily daily driver/tow rig duties....
Check the Tech....lots o info!