I second. There isn't much you can do to mod. I have a 2000GLS and all the mods I did are:
Goodyear TripleTred tires as opposed to stock RSA
Mobil 1 engine oil
SilverStar bulbs in the headlights
most serious mod: replacement of the bulbs in the seat heating switches and the mirror adjustment switches with LEDs, also added LEDs in the rear door window switches.
The next mod I'm planning is
Replacing the lock nuts with regular lug nuts