Do these mirrors bolt directly to my truck or do I need to drill new holes?

They attach at factory rocker panel points — no drilling required. Bolt straight to the existing holes your truck already has.

Will these stay stable at highway speed when extended out?

Manual mirrors rely on a friction-lock design at the adjustment joint. They hold position well on the highway, but you'll want to test-fit yours and verify the adjustment mechanism feels solid before towing heavy loads.

What fasteners do I need to install these?

Mounting hardware is not included with the mirror assemblies. You'll need bolts and washers sized for your truck's factory rocker panel holes — check your service manual or have a hardware store match them to your existing holes.