What confuses me about all this is that I have had 4 BMW's since they introduced the th USB option and evertime they have given me a Y cable. They even threw one in with the MINI we have too. So I assumed they were part of the deal.
2003 E46 M3 Estoril blue
2006 E90 320d M sport Le Mans blue
2008 E82 125i M sport Alpine white
2008 E88 135i M sport Titanium silver
2012 F21 M135i Estoril blue