Will this mirror plug into my factory wiring harness?

Yes—this is designed as a direct OEM-style replacement. Your factory power window switch controls mirror adjustment the same way the original did.

Do I need to remove the door panel to install this?

You'll need to access the mirror mounting points from inside the door. How deep you need to go depends on your specific door panel design—a service manual for your year will walk you through it.

Is the black finish paint or plastic?

The mirror comes finished in black. If you need a different color to match a custom paint scheme, you can prep and paint it like any other mirror cover.