I'm looking for the same info for my 92 gt. Let me know if you come across anything. I'm thinking it will probably mean changing the backing plate, lines, parking brake shoes, add rotors and some mechanical linkage adjustments on the parking brakes. found this in some other posts
Disc Conversion from Toyota Celica Online but I don't know if I'm going to go through the trouble. I think if I could just swap backing plates, cables and other parts over from the disc system that I would do that first. If not, it'll probably get left alone.