Do I need a new thermostat and housing when I install this?

Not necessarily. If your original thermostat is functioning and sealing properly, you can reuse it. That said, if you're already pulling the cooling system apart, many technicians replace the thermostat at the same time as preventive maintenance — your call based on mileage and condition.

Will I need new hose clamps or is there anything I should replace while I'm in there?

Hose clamps are worth replacing with fresh ones — they're cheap and prevent slow leaks down the road. Hoses themselves should be inspected for cracks or softness. If they're original to the car, new hoses are a solid move while you've got everything open.

What's the return process if this doesn't fit or I get a DOA unit?

Contact ModSupply customer service with photos and your order number — they'll walk you through the return or replacement. Keep the radiator packaging intact if possible; it protects against damage claims and speeds up processing.