LOL! I think I have the main exception. The NSX kits say to paint the chassis Flat Aluminum, because that's what the chassis
is. However, in later model years, the underside got color-matched.
Like Guiddy said, most modern cars are color-matched, but semi-gloss black is a safe bet if you think it'll look weird, or if you want to "cheat" your way around painting some underside detail.
