My rear brake set-up is pretty much all golf GTI mk2, discs, stub axles, and calipers and back-plates. Wheel bearings are pretty much standard across the entire VW range as far as I'm aware.
I made up new brake lines myself and the handbrake cables are Golf GTI Mk2 but shortened massively. I had to make new nipples to go at the caliper end and used the threaded adjuster ends (which go to the handbrake lever on the golf) to attach to where the standard polo cables go along the rear axle. If you use a pair of nuts, you can adjust the new cables really easy.
Don't forget you will almost certainly have to adjust the brake bias valve or you will have too much back brake and you will spin the car !
