Will this wing stay stable at highway speeds without reinforcement?

Yes. The one-piece FRP construction provides inherent rigidity. Confirm all fasteners are seated at OEM mounting points before driving, and the wing will maintain its position under normal highway conditions.

Does the trunk lid close normally with this wing installed?

Check clearance between your trunk lid and the wing profile before final fastening. If your vehicle has a power trunk or custom lid, verify closure mechanics once the wing is mounted at the factory holes. No modification to the lid or wing is required for standard setups.

What prep work is needed before painting?

Sand the surface with appropriate grit, wipe clean, and apply your chosen base coat and clear finish. The FRP is ready to accept paint without additional sealing steps.