update: water is still beading like it was day 1. so far so good.
(and the x sits outside 24x7)

I used it... use imperial hand glaze then throw that on on top of the paint. It does a great job and repels water liek you wouldnt believe

My local BMW dealer (Daniel's BMW) has it featured on the parts counter. I was looking at it the other day. I had never heard of it either but unusual of BMW to plug a no-name anything. I may pickup a bottle and give it a try.