Will this bumper fit my stock lower valance and undertray?

Check your vehicle's lower valance and undertray clearance before installation. The A Spec profile may require minor trimming or relocation of splash guards depending on your specific setup. Test-fit the bumper dry before committing to any permanent modifications.

Are there any fog light cutouts or sensor holes pre-drilled?

This bumper ships as a blank panel. You'll need to reference your OEM bumper's fog hole and sensor locations to determine where to drill. Dry-fit against your old bumper to mark cutout locations accurately, then drill or cut from the back side to avoid splintering the visible face.

What's the best way to prep this for paint?

Sand the surface with appropriate grit to scuff the finish, then wipe clean to remove all dust. Apply your chosen primer and topcoat per the paint manufacturer's instructions. FRP takes standard automotive paint systems well — work in a clean, ventilated space and follow cure times between coats.