If you are looking for motor mods, the intake is the largest restriction on the HO motor. For a budget build, Pick up an cobra/explorer intake and put it on. Other bang for the buck mods are gears(3.73 for auto 3.55 for manual is typical upgrade), subframe connectors. Leave the stock airbox. It is a "cold air" intake as it is and maybe throw a K&N panel filter on it. It definately isn't the prettiest thing out there but if you are looking to go faster on the cheap, just leave it for now. You can bump your timing to 14* from 10* which will help a little. Under drive pullies are really a gamble. You can run into cooling and charging issues... dependant on the climate you live in. I would just rock the stock pullies. There isn't much to gain there. Nothing that you would notice on the butt dyno. Start with the intake then save up for a set of heads. Suspension and brake mods are also a good thing to have. These cars are in their 20s and brake and handle like any other 20 year old car out there. Brakes are not adequate for a stock car IMO. With all the go fast goodies you will be adding, consider putting brakes up there too. Be safe.
kevin