Will this interfere with my trunk or bumper seal?

No. This is an add-on lip that mounts to the lower bumper area. It does not extend into the trunk jamb or seat gasket areas. Verify clearance with your own fitment by dry-fitting before final installation.

Should I use adhesive or drill through the bumper to install this?

Both methods work depending on your preference. Adhesive bonds offer cleaner aesthetics with no visible fasteners; mechanical fastening (drilling) provides the most secure hold. Prep the mounting surface thoroughly before committing to either method, and reference your vehicle's OEM bumper structure to avoid hidden clips or support brackets.

Does this need clear coat protection?

Carbon fiber benefits from a UV-protective clear coat to maintain its finish and resist oxidation over time. Apply your chosen automotive clear coat according to manufacturer specs, and wet-sand the panel lightly beforehand for proper adhesion.