Will this work with my vehicle's factory roof rails?

As long as your crossbars are flat (not round or T-slot), this basket will clamp down securely. If you're unsure about your specific crossbar profile, measure the top surface width — flat bars typically run 2–3 inches across.

Do I need to drill holes to mount this?

No drilling needed. The basket clamps directly to flat crossbars using the included mounting system.

What's the weight limit I should stick to?

Weight capacity depends on your vehicle's roof load rating and your crossbar system — check your owner's manual. The basket itself is built solid, but your car's structure sets the real limit.