Will this interfere with my trunk lid or bumper seal?

No. The A-Tech design is engineered to sit cleanly below your factory bumper line without binding against seals or creating gaps. Your OEM bumper will close normally.

Do I need to drill through the bumper to mount this?

No drilling required. This lip uses factory mounting points on your bumper assembly. Simply align and secure using the existing attachment locations on your bumper.

Will this stay stable at highway speeds?

Yes. The one-piece FRP design and factory mount points provide solid rigidity. As long as you torque fasteners evenly and use an appropriate adhesive or mechanical fasteners as intended for your install method, this lip will remain stable under normal driving conditions.