How much tire and wheel clearance do these add?

Over fenders expand the opening to fit wider setups, but exact clearance depends on your wheel offset, tire width, and suspension geometry. Dry-fit or consult with your installer to confirm clearance before committing to installation.

Do these require drilling or do they bolt to factory mounting points?

Installation method not specified — verify with your installer or supplier on fastener placement and whether any drilling is needed at your specific mounting locations.

Will these work as standalone fenders or do I need the full widebody kit?

These are designed to integrate as part of the complete widebody system. Installing them alone may result in fitment gaps or panel misalignment — plan to use them with the rest of the kit.