OK, I got this idea. I got a Mr. Clean car wash system and it dries without leaving spots. It has a water filter that filters out minerals so it doesn't leave spots when it dries. But the filter costs $$$.

If you have a dish washing machine, you will know that if you use Jet Dry in the machine, you won't have spots on the glassware, even though the water going into the machine is not filtered. OK, so suppose a person did this - wash your vehicle (just use regular car wash, not the Mr. Clean system). Then using a sprayer that attaches to the hose like you would use to spray a concentrated fertilizer, put in the sprayer Jet Dry and it will mix with the water. Rinse the vehicle with that. Now, wouldn't the vehicle dry with no spots? You now would not need the Mr. Clean system at all and would not need to chamois the vehicle.