I never use touchless car washes. Normally if the car has more than just dust on it, I go to the coin op wash (the water here isn't recycled) to clean the underneath and get the coarse sand, etc off which works better than the garden hose at home. After I bucket wash the car at home because there is less of a chance of getting scratches after the coarse stuff is gone.
I suppose if you go through the touchless wash and don't let them try to dry it the same process would work.
Black cars are a pain in the azz. They look great when they are clean, but they are never really clean for long.
2008 Sky Redline
Black Onyx Red/Black Leather
Single Disc Monsoon
Picked up 9/04/07