Do I need to remove my entire front bumper to install this bracket?

Depends on your bumper's current condition. If it's already off or loose, access is straightforward. If it's attached, partial removal or bumper lift will give you clear access to the mounting points. Nothing about this bracket itself requires full disassembly.

Will this work if I've already modified my bumper cutouts for fog lights or sensors?

This bracket mounts at the structural reinforcement points behind the bumper cover, so existing cutouts won't interfere with installation. Your modified bumper cover will bolt to this bracket the same way it did to the original.

What fasteners do I use to attach this bracket?

Reference your vehicle's service manual for the correct bolt size and torque specifications for your model year. Factory hardware at those mounting points will vary—don't assume what came out before will work with this replacement.