88.5 was a ( laughing ) Major change over model. Dash board went from round vents to square , stereo was mounted differently and had a re-geared 5th gear in the transmission.
This may have been the year that Suzuki went to a twin line braking system on the rear of the Samurai.
91 ushered in the EFI version.
Other than those few changes there all about the same.