Will this interfere with the trunk lid or seal?

No. The Type M profile is designed with clearance for standard trunk operation. Verify fitment before final adhesive or fastener installation if your trunk weatherstripping is non-OEM or heavily reinforced.

What's the best way to mount this — adhesive or bolts?

Bolt-on is recommended for long-term durability and adjustability during fitment. Existing rear panel mounting points accept standard hardware; adhesive-only installation is not recommended for performance components subject to wind load and vibration.

Will this stay stable at highway speeds?

Yes, when properly secured with fasteners. Ensure all mounting points are torqued evenly and that the lip sits flush against the panel before driving. Vibration or movement at speed indicates loose fasteners — retighten before continued use.