Do these mount at the factory mirror attachment points?

Yes. These are designed for direct bolt-on installation using existing factory mounting holes—no drilling or frame modifications needed.

Will these stay stable at highway speeds?

The sealed housing and factory mounting design keep the assembly tight and vibration-free. Heavy-duty construction handles sustained highway operation without rattle or movement.

Do I need to splice into existing wiring?

Installation method and wiring integration details are not specified in the product data—verify compatibility with your mirror harness before committing to installation.