Things to look for
Aero wheel package (standard equipment on 91 & 92 5-door turbos)
Three spoke 16" Aero wheels
Lower, stiffer suspension
As close to an Aero as you can get without having an Aero.
9000 S and most other models are otherwise generally "loaded"
Base 9000 model less so
Turbo models are much more powerful than non-turbos
Potential for having been abused is obviously somewhat greater