91 Would be a good one.
I have to look and see what all the differences are for the airbag and clock-spring etc., between the years. jrichker likely has that info on-hand somewhere.
The 91-93 wire colors are different for some of the wires. My source for the wiring diagrams has been www.veryuseful.com.
I have an 89 Mustang 5.0 harness that was removed from a working car before some Florida Bozo sideswiped me and totaled the car.