If it's a 2wd then xr4i discs/calipers at 260mm will fit, IF the wheels are large enough(14" minimum), if you have 15" or more cossie 2wd calipers and discs are a straight fit, all you need to do is to tap a thread into the hole of the hub where the existing brak bolt passes through, it is already the right size for tapping out to 12 x1.5 I think it is, will need to measure, I did this on my mk1 2.0gl, this gives a massive gain, add to that drilled/grooved discs and some nice redstuff pads with braided lines, you'll be amazed at the difference, you could just do the bits as you have the money, ie just use any cheapo pad to start with ect std discs std brake lines, even the cheapo std ebc pads have kevlar and are excellent.
tabetha