Do these mount to my factory roof rails without modification?

Yes. These bars attach directly to factory mounting points on your roof rails — no drilling or welding required. Just bolt them in place using the existing attachment hardware on your Highlander.

What kind of load can these bars handle?

That depends on your vehicle's roof load rating, which is listed in your owner's manual. These bars are designed to support standard roof boxes and cargo baskets within manufacturer limits. Distribute weight evenly across both bars and don't exceed your vehicle's capacity.

Will I need to purchase any additional mounting hardware?

Mounting hardware is not included with these bars. You'll need fasteners compatible with your factory roof rail system. Check your owner's manual or test-fit before purchasing to confirm hardware specs.