Does this fit over my existing bumper or do I need to remove it?

This cover bolts directly to the factory bumper structure underneath. You'll need to remove the old cover first, but the core bumper beam stays in place — straightforward swap.

Can I paint this, or does it have to stay chrome?

It ships chrome. If you want to match a different color, the hard panel surface can be prepped and painted — just plan for sandpaper and primer work before spraying.

Are the mounting brackets included, or do I reuse the old ones?

Mounting hardware is not confirmed with this unit. Inspect your existing brackets during removal — most are reusable if they're not bent or broken. Have replacements on hand just in case.