Do I need to sand and prime this before painting?

Yes. Sand the surface to prep it for adhesion, then apply your choice of primer and paint. FRP finishes best when the base is properly prepped. Refer to your paint manufacturer's recommendations for surface prep steps.

What hardware do I need to install this grille?

The grille assembly ships as a single piece. You'll need to source fasteners compatible with your bumper assembly and existing mounting points. Check your vehicle's service manual or OEM documentation for fastener specs and hole locations.

Will this fit my existing bumper cover, or do I need a new one?

This is a grille replacement, not a full bumper. Verify that your current bumper cover or fascia has compatible mounting points for the grille opening. If your bumper design differs significantly from stock, test-fit before final installation.