Does this bumper have fog light cutouts pre-drilled?

No. This cover arrives as a solid panel without pre-cut fog light holes. You'll need to measure and cut those openings yourself if your build uses aftermarket or factory fog lights.

Will I need to modify this for a lower valance or splitter?

The bumper supports bolt-on lower valance and splitter setups through its factory mounting structure. Any custom splitter design will require drilling or epoxying additional mounting points into the FRP panel—plan accordingly before finishing.

Does this require sensor cutouts, or is it compatible with bumper sensors?

This is a solid bumper cover with no pre-drilled sensor holes. If your build uses factory or aftermarket parking sensors, you'll need to cut those openings after fitting the bumper.