Will this interfere with my trunk seal or bumper panel fitment?

No. The lip mounts to the lower fascia and does not contact the trunk seal or rear bumper area. Verify your OEM front fascia is unmodified and that no aftermarket splitters or splitter brackets are already installed before mounting.

Should I use adhesive or drill through the FRP to mount it?

FRP is strong enough for both methods. Adhesive mounting avoids fastener holes and keeps the finish clean; drill-through mounting offers redundant security. Choose based on your intended use and willingness to make permanent holes. Either approach works on solid FRP.

Will this lip stay stable at highway speeds?

Yes. FRP's rigidity prevents flex or vibration once properly mounted. Ensure all contact points are clean and dry, and follow your mounting method (adhesive cure time or fastener torque) before driving. Inspect mounting points weekly for the first month to confirm everything remains secure.