For street use with occaisional tracking I don't think it's necessary to dump $3000 on a big brake kit (provided you'd want to do both front and back), I was considering the same thing but for the amount that I track it's not worth it.
You're best bet would be to do a full brake tune up. Replace your fluid with a DOT5 fluid (higher boiling point) change your rubber brake lines to stainless steel braided ones, get a nice set of slotted / dimpled or drilled rotors (rotora is a nice brand) and get a decent pad ( I also personally like the EBC Red Stuff pads, Yellow Stuff are nice and more suited to tracking, they WILL wear alot faster)
Other than that, there's not much you can do without upgrading to big brakes or retrofitting MK4 calipers, the brakes on the MK3's were the car's downfall, far too underpowered for the car weight & speed the car could attain.