Do these mirrors mount at the factory location without drilling?

Yes. These are designed as direct bolt-on replacements at the stock mirror mounting points. No drilling or modifications required.

Will the power heated function work with my truck's existing electrical harness?

These mirrors are wired for your truck's power and ground circuits. Have your harness inspected before installation to confirm compatibility with heating and adjustment circuits.

How stable are these mirrors at highway speeds while towing?

The towing-specific design provides rigid mounting and extended geometry to hold position under load and wind load. Do not adjust mirror angle once hitched and underway—secure them before departure.