maybe an unpopular suggestion i know, but instead of putting your first chunk of change into underhood mods you should spend them elseware, to build a foundation for yourself.
obviously go ahead and do the full fluid service and tune up. at this time upgrade to an intake, NGK'*, and add a transmission cooler. replace the belts and hoses at this time. drop down to a 180 T-stat.
then get yourself a fresh set of brakes and get everything there in top condition. you shouldn't make it go faster until you've made it stop faster.
then, depending on how much money you have left, invest in a good set of perfomance tires. tires are the only part of your car that actually touches the road. nothing else will have such a drastic effect on all areas of your cars perfomance as good tires.
if you have any money left over after this, i would do a small pulley upgrade.
now you're not going to have earth shattering perfomance following my suggestions, but you will definatly have a sound base for later perfomance upgrades.
1993 Buick Lesabre Limited "Elizabeth" Light mods
1995 pontiac Trans Sport "The Vandal" On To A Better Home