Will this bolt straight into my engine bay, or do I need to modify anything?

This radiator uses factory mounting points — no drilling or bracket modification needed. Bolt it in place where your original sat and connect your hoses back up.

What's the difference between the automatic and manual versions?

Automatic transmissions generate additional heat that flows through transmission cooler lines integrated into the radiator. The manual version omits those lines since there's no automatic transmission fluid to cool. Order the version that matches your drivetrain.

Do I need to flush my cooling system before installing this?

Yes. Drain the old coolant completely, flush the system with distilled water if it's been a while, and refill with fresh coolant rated for your vehicle. Old coolant sitting in a new radiator accelerates internal corrosion.