whats different about the 89?

Usually the year spreads are 87-89 and 90-93

Between 89 and 90 there were a few changes....mostly interior. The interiors changed for one, smaller headrests, different dash, addition of airbags and removal of tilt. Colors changed as well.

That's about it really. The bigger fenders started in 1991. Mass air began in 1988 (cali only)