mkviken - this is the part number: VWRPA004. I went for 20mm drop front and back... the front can be set to 25mm drop if wanted.
have to say they have really improved the ride quality over the PI Springs fitted by the previous owner... coupled with Sport mode on the ACC the car goes through corners very nicely with little body roll... felt a bit like the time I took a works cooper S out (although the GTI is more "grown up"... i.e. less "crashy")