Does the clear coat need to be sealed once painted?

Once you apply your chosen finish and clear coat, standard automotive UV protection will preserve the color and gloss. Carbon fiber itself does not yellow under UV exposure the way some composites do, but a quality clear coat layer maintains your paint's appearance long-term. Apply clear coat per your paint manufacturer's recommendations.

Should I seal the edge where the trunk meets the body?

Yes. After installation, seal the perimeter seams with automotive caulk or gasket sealer to prevent water and debris from entering the trunk cavity. This is standard practice with any trunk replacement and keeps the interior protected.

How should I prep the surface before painting?

Sand the primer surface with medium-grit sandpaper to create proper adhesion for paint. Wipe down with a tack cloth to remove all dust. Follow your paint system's surface prep guidelines — the primer layer is designed to accept topcoat directly.