I noticed differences in:
Seats: Older models (Pre xx/94) have front seats that have the thin backrests, newer models have the thicker backrests, i feel it more comfortable.
Climate control: Pre 96 models have the manual climate control with the knobs.
Remote central locking: Older models (Pre 95) have a normal looking key with a torch. You cannot remotely lock the car.
The speedo cluster as discussed
The 3rd brake light on the rear shelf. Older models dont have this.
Front bumpers. The pre 97 models have front bumpers that have many slots in the airdam, while the newer models have 1 big rectangle.
I also understand there are more differences in the late 97/98 models.