Well, I've done it too (my auto mechanic did actually)
I bought all the parts on ebay due to the best price. I paid €120 plus shipping for a calliper kit that included two brake callipers, two carriers and a set of pads. I also paid €119 (shipped) for a set of Zimmermann drilled/coated discs. I considered the brembos too, but they were more expensive and heavier than the zimmermanns. The 312 mm zimmermann brake disc weights 8.3 kg while the brembo one weights 8.6 kg. In comparison, I put the old 288 mm disc on a scales and it shown 7.3 kg. So I added 1 kg to the unsprung mass which I, to be honest, didn't notice during first 80 km of driving. Here are some pics.
Again, a huge thanks to @golfdave for this amazing write up!
Again, a huge thanks to @golfdave for this amazing write up!