Do I need the left bracket too, or can I use just this one?

You'll want both brackets for proper support and alignment. This is the right side only — order the left bracket separately to complete the front bumper assembly.

Will this work with aftermarket bumper covers?

Yes. It mounts at factory points, so most aftermarket covers designed for fifth-gen Mustangs will bolt up cleanly. Test-fit your specific bumper before committing fasteners.

Does this require welding or modification?

No. It uses the original mounting locations, so install is bolt-on with no cutting or welding needed. Standard hand tools and a jack are all you need.