There are quite a few mods avaliable for these cars. If you are looking for visual things, you can recontent some of the pre/early 98 things. For example you can recontent the dash clock if your 98 is a late 98 car. Also, you can pick up a pre-98 antenna base which look pretty nice, better than the post 98 one IMO.
Here's a pic of my modded Pre-98 clock. It was modded to light up white.
Here's a shot of the Pre-98 ant. base
