Are the fog light cutouts pre-drilled?

Yes. The fog holes are factory-sized and ready to accept your existing fog light assemblies — no enlargement or modification needed.

Can I install this without removing my lower valance?

No. The valance must be unbolted from the frame to slide the new bumper into place. Once mounted, both pieces bolt together as original.

Do I need to fill or modify the sensor holes before painting?

Only if you don't plan to run factory parking sensors. If you're keeping the sensor system, leave the cutouts open — they'll be covered by the sensor trim rings during installation.