Will this interfere with the OEM trunk seal or bumper gap?

No. The factory mounting points are engineered to accept this profile without altering the bumper's position or sealing surfaces. Your OEM gaps and seals remain unchanged.

Does this require drilling, or does it use existing holes?

It uses existing factory mounting points — no drilling into the bumper cover. Locate your vehicle's OEM attachment holes before installation to confirm compatibility with your specific configuration.

How stable is this at highway speeds?

FRP construction paired with factory mounting points provides solid durability at speed. Ensure fasteners are fully tightened and inspect mounting points regularly to maintain stability during normal driving.