The most effective way of improving handling without lowering is rims and tires. Larger diameter rim with a much lower profile tire is very beneficial. Also, if you get custom rims that you can pick the backspacing lower the offset some more, you gotta becareful when doing this because even with a factory size tire theyll rub.
At any rate, larger rim lower pro tire, pump the front to 42 keep the rear @ 36. Also, another thing you can do is get larger sway bars. On my '85 I had 1 15/16" fr and a 7/8" rear, but my car weighed less than yours. A few more things, fr. strut tower brace, rear shock tower brace. Sub frames, panhard rod, poly bushings, and so on. But the most noticeable improvement will be from the wheels arnd tires. Make sure you get some nice sticky ones.
-P.