Well sense it is a 90 model you could gain a little power from some 94+ cams and a 94-95 intake manifold. Then get a header, 2.25" mandrel bent exhaust and a intake ( any brand will work just make sure you get a quality fliter like K&N though). And you will see some improvements for not a lot of money.
I have a set of cams and a intake manifold if you are interested. Let me know if you are.
