Will this interfere with the factory bumper seal or undertray?

The lip mounts to existing factory points and sits flush with the bumper assembly. Check clearance with your vehicle's undertray before fastening — you may need to trim or adjust the undertray tabs slightly depending on how aggressively your lip is positioned.

Should I use adhesive, fasteners, or both?

Factory mounting points are designed for mechanical fasteners. Adhesive alone is not recommended for long-term durability at speed. Use stainless steel fasteners at all mounting points; most DIY installs combine fasteners with trim-panel adhesive for added security and vibration damping.

How stable is FRP at highway speeds?

FRP is rigid enough for highway use when properly fastened to all mounting points. Ensure every factory hole is secured and there are no loose edges. Inspect fastener torque after your first 100 miles of driving, then periodically — vibration can loosen hardware over time.