Being chrome, you should scuff them GOOD with a red scotch bright pad by hand, I would highly recomend an adhesion promoter, I like a product called "bulldog" its an aresole that you apply 2 LIGHT coats before the paint. Theres no need to use any primer, depending on how much you want to spend you can use a good spray paint, and a spray clear coat. If you want a better tougher quality I would recomend a single stage urethane paint.