Do these use the factory mounting holes?

Yes — these bolt to the existing mirror mounting points on your door. No drilling or bracket modification needed.

How do I wire the power controls and LED markers?

The power harness connects to your vehicle's electrical system. Consult your vehicle's service manual or a professional installer for proper grounding and circuit routing to avoid interference with existing switches.

Will these mirrors stay stable at highway speeds while towing?

The powered adjustment mechanism is designed for towing use. Once positioned and locked, the glass is held by the motor assembly. If you experience vibration, confirm the mounting bolts are tight and the mirror is fully seated against the door.