Will this fit my factory mirror housing without modification?

Yes. This lens mounts at factory points using the original mirror bracket — no drilling or adapter hardware needed. Swap it straight in.

Do I need to remove the entire mirror from the door?

Not necessarily. Most installs allow you to access the lens from inside the mirror housing. Check your mirror's backing plate design first — some let you swap the glass without full removal.

What tools do I need to install this?

A screwdriver and maybe a panel removal tool if you need interior access. Nothing specialized. Take a photo of your current lens mounting before you start so you know how to seat the new one.