Hi Mal,
from what i remember the fitting was quite easy, the kit i bought from Mick at Redline was about £650, it came with aeroquip flexible brake lines which were slightly shorter than the ones i had on the S4 so did not use them, not sure if the connections were unf, but it is easy to have connections made with metric ends,i have a short length of kunifer pipe from the flexy to the caliper which thinking about it i am sure they were unf, Mick should be able to confirm.
The only modifications i needed was to have about 4mm machined off the two mounting pads on the caliper mounting plate that bolts to the vertical link to centralise the caliper to the disc and as i have cycle wings fitted i had to alter the wing stays, no problem for you as i think you are on full length wings.
Master cylinder can remain as standard as bore size is the same, i have a dual cicuit master cylinder from an S3 fitted, that needs a chassis modification to fit.
Rear brakes are standard drums with uprated linings.
Braking is really improved now, i used to have to really stand on the brake pedal before where as now a more gentle pressure is required, took a long time to adjust to the extra performance.