Will this interfere with the trunk seal or bumper edge?

The lip mounts to the lower rear bumper and sits below the trunk line, so clearance is not an issue during closure. Verify fitment against your specific bumper cutout before drilling to confirm alignment with your vehicle's rear panel geometry.

Should I use adhesive or drill mounting holes?

FRP responds well to both methods. Adhesive alone works for light-duty mounting, but drilling and fastening offers permanent security at highway speeds. Choose based on your intended use and whether you want reversibility — adhesive is easier to remove later if needed.

How stable is this at speed with minimal additional support?

As a single-piece unit, it's designed for secure mounting and won't flex or rattle once properly fastened. Proper surface prep and fastener selection matter more than the material itself — sand the mounting points, use stainless hardware, and tighten evenly to lock it in place.