Do these covers require any hardware to install?

Installation hardware is not specified in the product data — test-fit the covers first to confirm whether you'll need adhesive-backed mounting or fasteners before committing to either method.

Will the chrome finish hold up outdoors or will it tarnish?

ABS with a chrome finish is UV-resistant and designed for exterior use. Keep them clean and dry when possible to maintain the shine; standard car wash soap works fine for maintenance.

Can I remove these later without damaging my original door handles?

As long as you verify the mounting method during test-fit, most cover systems are fully reversible — just clean off any residue from your factory handles and you're back to stock.