Will this interfere with the factory trunk seal or bumper fitment?

No. The GT Concept profile is designed to bolt within the existing bumper assembly without contact points that would compromise seals or alignment. Verify your bumper mounting hardware is tight before installation.

Does the lip need primer before I paint or clear it?

The clear coat finish provides UV protection as-is. If you plan to repaint, sand and prep the surface before applying your chosen primer and topcoat system. The carbon weave should be fully sealed to prevent moisture ingress.

How stable is real carbon at highway speeds compared to fiberglass?

Carbon fiber is significantly stiffer than fiberglass, which means less flex under aerodynamic load and better structural integrity at sustained speeds. The hand-laid construction ensures consistent weave density and minimal vibration. Ensure all mounting points are secured per factory specifications before extended highway driving.