Will this work with my OEM fog light cutouts and lower bumper sensors?

The wide-body design is engineered around factory sensor hole locations on the lower valance. Before installation, reference your vehicle's OEM bumper hole positions to confirm alignment, then mark and drill accordingly on the FRP surface.

How should I prepare the bumper before painting?

Sand and prep the surface with appropriate grit to create adhesion for your chosen primer and paint system. FRP absorbs moisture, so sealing the back side with epoxy primer before final topcoat is recommended to prevent resin bleed-through and long-term finish breakdown.

Does the lower valance sit flush with the factory air dam, or does it extend beyond it?

The valance is designed to integrate with OEM lower air dam geometry. The exact gap depends on your vehicle's original bumper condition and alignment. Check fitment in place before final fastening to ensure the valance sits cleanly relative to the existing lower panel.