Do these use factory mounting holes?

Yes—these mount directly at OEM attachment points with no drilling needed. You're bolting them where the original mirrors sit.

Will they stay stable when I'm towing on the highway?

Manual mirrors are rock-solid once adjusted. Set your angle before you go, and they hold position through highway speeds. No vibration or drift.

Do I need to run new wiring?

No wiring required—these are fully manual. Adjust them by hand through your window. No power motors, no switches, no complications.