1. Maintanance
2. High Flow Y-Pipe
3. Larger Brakes (96'-upgrade atleast)
4. New Struts/Springs, New Bushings(including subframe), Subframe connectors.
5. Nitrous
Yes, No.4 has more than one mod.. however, IMHO the suspension system needs to be taken as a whole. In other words, get the suspension set right as a single mod to the suspension will not have a great effect on the "gain meter". You could slap on the best set of SFC's on your car, but with worn struts and springs the car is still going to handle like crap.
Sure you could spend the money to get EH manifold, BBB's, Cams, a MAF, etc etc etc... But in reality, you'll end up spending more money on the motor and less on the suspension and brakes where the SHO really needs help. With the above mods, the car will be fun to drive, handle very well, brake like it has never before, and when you need alittle extra bump for those fun spots running down the highway, it's just a flick of a switch away.
But OTOH, if you have the money to do all the mods or find great deals, then by all means knock yourself out... every little bit helps.