I'd go for a LSD, but thats a lot of money.... I got a disk brake conversion, but more for the street than autocross... Nice to have, but it wont help you much on the track (especially when your car is a slow as mine).

Even with just 92 hp, I've felt the need for a limited slip on the autox course... Its a big investment, but a logical step, and since youre already in mod, it shouldn't change your class.

That said, sway bars are a lot cheaper. You might look into crx si swaybars. My friend autocrosses with those on his 89 civic si (when the triumph isn't running--which is pretty often), and they work pretty well for him and are a cheap junk-yard buy.