I know this is heresy on this board, but our automobiles' finishes are much tougher than we give them credit for being. Certainly they can scratch and mar easily, but regarding chemical resistance, they're tough. Look at the abuse they receive in areas which use salt and/or calcium chloride frequently in the winter.
I've used Purple Stuff diluted 1:1 with water for a quick and one time wash to get rid of wax buildup with no residual effects. however, as soon as I had rinsed and dried it, I immediately went ahead with an
AIO and sealant coverage. 1991 Red Buick Reatta; original paint with clearcoat.