You CANNOT use wheel acid on aluminum rims, because it will screw them up. I know from first hand experience because like you said I had a friend who worked for a professional detailer. Took my parents' minivan in to have him clean it and the acid ended up taking some of the finish off the rims. So as long as you have the stock Contour SE rims, you will be screwing yourself if you put acid on them.
But it does work well, especially on steel.
