Will this interfere with my trunk or bumper cover when the hood opens or closes?

No. The lip is mounted to the lower fascia and sits below the hood line. Your factory hood and trunk operation remain unaffected.

Can I use adhesive, or do I need to drill through to mount this?

This lip uses factory mounting points, so fasteners go into existing holes. No additional drilling required. Adhesive is not recommended for this application — use mechanical fasteners for long-term stability.

Will this stay secure at highway speeds?

Yes. Properly fastened to factory mounting points, the lip is engineered for highway use. Make sure all fasteners are tightened securely before driving, and check them after the first 50 miles to confirm they haven't shifted.