Will this lip interfere with my trunk seal or rear bumper gap?

No. This is a front lip positioned at the lower fascia; it does not extend into or contact the trunk seal area. Your rear clearances remain unchanged. Verify your vehicle's OEM bumper mounting points before installation to confirm your specific setup.

Should I use adhesive or drill through the factory mounting holes?

Factory mounting holes are designed for bolted installation. Use the existing holes with fasteners — this method is cleaner, more durable, and reversible. Adhesive-only mounting is not recommended for a front lip that absorbs road impacts and vibration.

How stable is this at highway speed?

FRP front lips are engineered to handle road speeds without lift or flutter when properly secured to factory mounting points. Ensure all fasteners are tight and double-check after your first 50 miles of driving. Any looseness will amplify at speed.