1984... must be a very rare early prototype, probably worth millions!!! I jest of course, but the reason we ask is that a simple upgrade path from a pre-facelift is to fit the 325mm discs and calipers from the facelift (and also E46 330ci). That would be the simplest and cheapest upgrade option fro you assuming you are running bigger than 16" wheels.
But your details are so sketchy I'm not even sure what you are intending to use the car for? Your title suggest you are looking for new calipers but if it's just fast road, upgraded pads are probably all that you need.