Several ways to go. You can add a flattening agent to single component paint, or you can put a satin clear coat on a base coat clear coat system. Another option is to use something like Duponts hot rod black, which is a catylized enamel, and not real cheap, but from what we understand pretty good. It is what we are considering on my Son's RPU.

Some people also use John Deere black and similar paints, but I have seen mixed reviews on the outcome and longevity.

Don