Good topic I know a bit about it, my company produces car wash chemicals based on Nano-Technology over here in Switzerland and we sell to the big guys like DaimlerChrysler (for e.g. the final touch on their Maybach) or Würth. Whatever water you use, if you don't dry the car, you get spots. Even after using the best chemicals on Mother Eart (i.e. our "Vison Supershine" stuff. Ok ok, I know that sounds like a commercial) you end up with water spots on a car that hasn't been dried with a cotton towel or leather. It's the minerals etc. in the water, not the chemicals. I own several classic Porsche and never wax or polish them. No kidding. I just wash them with our shampoo that cleans and protects (longtime) at the same time. Additionally, one gets up to 100% more shine on older paint (proofen by independent institutes and DaimlerChrysler). There are "wash and wax" products out there that claim the same, but 99% of them are wax based which means that after a few days out in the sun etc, the shine and "protection" of even the best wax is gone.... The only thing left on the paint then is some unwanted, sticky residue of broken down wax. Then you wash again, wax again, wash again, wax again etc etc. I rather drive or service my cars than wash them all the time.... Wax is ok but has only a very short life span. Important: Cars will get dirty again with our stuff too (there is no such thing as a "selfcleaning surface" yet), but will be much easier to clean. And the paint will always look like freshly polished and waxed. Anyway, whatever shampoo you use, never in the sun, never on a hot car, never without drying.

BTW: Did I mention that we should be able to supply you with free samples from our partner in Oregon soon? Seeing is believing :-)