Do I need any additional hardware to install this?

The assembly mounts at factory points, but fasteners and clips are not confirmed as included. Verify your door panel hardware before installation — you may need to reuse existing bolts or pick up trim clips separately.

Will this work if only my motor is bad, or do I have to replace the whole regulator?

This is a combined assembly, so you're replacing both the motor and regulator together. If your regulator itself is damaged, this solves the problem in one unit. If only the motor failed and the regulator is fine, you're still getting a complete tested assembly.

How difficult is the installation process?

Installation requires door panel removal and unbolting the old unit from factory mounting locations. Door panel removal typically demands a trim tool and basic hand tools. If you're comfortable with interior panel work, this is a straightforward swap — refer to your service manual for torque specs and exact fastener locations.