Will this interfere with my trunk seal or weatherstripping?

This is a front lip, so it sits at the lower bumper area and does not contact trunk components. No seal interference.

Can I use adhesive instead of drilling, or do I need to drill mounting holes?

Mounting method depends on your preferred installation approach. Verify the bumper surface prep and your vehicle's cutout configuration before committing to adhesive or fastener mounting.

How stable is this at highway speeds?

FRP rigidity and factory-matched geometry keep the lip seated firmly under normal driving conditions. Ensure all mounting points are fully secured and check periodically for any movement or looseness.