Will these diffusers interfere with my trunk seal or brake light housing?

No. The diffusers are designed as add-on panels that mount forward of the bumper edge and do not extend into the trunk or light cavity. Verify your rear bumper's current fitment before drilling or bolting to confirm clearance with your specific bumper generation.

What's the best way to secure these — adhesive or drilling through the bumper?

Bolt-on mounting to existing factory attachment points is the recommended method. This preserves the bumper integrity and allows for removal or adjustment without permanent modification. Check your owner's manual or the bumper's underside to locate mounting holes.

Will FRP diffusers stay stable at highway speeds?

Yes. FRP rigid panel construction is designed to maintain shape and resist flex under airflow. Proper mounting and torquing of fasteners ensures the set stays secure. Confirm all mounting hardware is fully tightened before extended driving.