Well, u have to sand anyways to make the surface to look good or the paint job it will look like WRAP! Somebody mentioned to strip all the paint off, you can do that also. The question is if the paint is falling off or you have some chips in the paint due to accidents or pebbles? Big difference between both of the situations. If the paint is peeling off u are better stripping the whole paint off, sand anyways.. find a primer for aluminum surfaces, have no idea if upol does it, dont remember it does. Paint and clear.

Yes if you screw up u can take the paint off with paint remover. Or if it doesnt look as bad u can sand imperfections and paint over it (retouch).