Sorry about that. It's the suspension upgrade kit (see link):
http://cairns.mistral.co.uk/cgi-bin/...ade_jcw520.htm
It's made by Spax specifically for
JCW Garages. It comes as 4 struts, 4 springs. You'll need to use the strut tops from your current suspension. Full ride height adjustable. Single rate adjustment with 10 settings. Spax also sell these direct, but they are yellow and have 28 settings on the rate adjustment (it's just a finer adjustment over the same range), but BMW won't cover these as they are sold outside the BMW network.