Will this install without removing the entire mirror housing?

Yes. This lens swaps directly into your existing mirror frame. The glass pops out and the new one seats in place — no need to unbolt the whole assembly from the door.

Do I need any fasteners or adhesive to install this?

Installation hardware is not included with this lens. You'll use whatever mounting method your mirror frame employs — whether that's clips, tabs, or adhesive. Check your mirror housing before ordering to confirm the attachment style.

Is this lens the same size as the factory original?

This is engineered to factory specifications for your 4Runner generation. Verify fitment against your vehicle's current mirror before installation to ensure compatibility.