Will this wing stay stable at highway speeds?

Yes. The CPR profile and hand-laid carbon fiber construction are engineered for aerodynamic stability. Verify that mounting fasteners are torqued evenly and fully seated before driving; check them again after your first 50 miles to confirm no settling has occurred.

Does the trunk lid close normally with this wing mounted?

The CPR profile extends beyond the stock panel height. Measure the clearance between your closed trunk lid and the wing's trailing edge before final installation to confirm fit with your specific liftgate geometry.

What finish should I apply to bare carbon fiber?

Sand the surface with fine-grit abrasive and prep it as you would any composite panel before applying your choice of clear coat, paint, or resin finish. UV-protective clear coat is strongly recommended to preserve the weave texture and prevent UV degradation over time.