I use the Klasse twins and now I'm looking for a quality car wash that won't strip or interfer with bonding of Klasse. I've heard good things about Sonax but I'm not able to find a place to buy it online. Can someone help me out. I've also heard the BMW car wash, depending on who's writing, is either the P21s or the Sonax. Does anyone really know for sure? For all those who have tried these products can someone please tell me what their using now and why they switch.