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

The racer style lip is designed to mount to your existing rear bumper without contacting the trunk seal. Verify clearance with your bumper's mounting points before final installation to ensure the spoiler sits flush and doesn't obstruct lid operation.

Should I use adhesive or drill through the bumper to install this?

Both methods work depending on your preference for permanent vs. removable mounting. Adhesive offers a cleaner look with no holes; drilling provides a more secure long-term bond. Choose your method before prepping the bumper, as surface prep differs for each approach.

How stable is this at highway speeds?

The single-piece FRP construction is rigid and stable once properly mounted. The racer-style profile adds minimal aerodynamic load. Ensure all mounting points are tight and the surface is clean before installation for maximum stability.