Will this interfere with my trunk seal or liftgate operation?

The lip extends from the lower bumper and does not contact the trunk lid or seal. Confirm clearance by checking your vehicle's exact bumper geometry before final positioning.

What surface prep is needed before paint?

Sand the surface with appropriate grit to scuff and remove any dust, then apply your chosen base and clear coat. Proper adhesion depends on a clean, prepped surface.

Does this affect brake light visibility or cutout?

This is a lower lip and does not interfere with brake light housings. Verify your brake light layout and ensure no light beam is obstructed by the lip's final position.