Do I need to replace my O2 sensor or heat shield when installing this?

Check your current O2 sensor location — it may need repositioning if your header design moves it. Heat shielding is recommended if the header runs close to plastic intake components or wiring. Test-fit before committing to modifications.

Will this header need any surface prep or coating before I bolt it on?

Stainless resists rust on its own, but bare metal can discolor under heat. You can install as-is and let the exhaust patina develop naturally, or apply a high-temp ceramic or metallic coating beforehand if you want a specific finish.

What kind of gasket material do I need between the header and engine?

Use a quality multi-layer steel gasket rated for stainless headers — this prevents leak-down and handles thermal cycling. Refer to your vehicle's service manual for torque specs on the manifold bolts.