Do these bolt straight to my engine, or do I need new gaskets and hardware?

They bolt to factory mounting points. You'll want new gaskets between the header flanges and your engine block — don't reuse the old ones. Fasteners aren't included; use the hardware from your factory manifolds or pick up a stainless steel header bolt kit.

Will these work with my stock exhaust system downstream?

Yes. The outlet diameter matches factory spec, so your stock piping, muffler, and resonator will bolt right on. If you're planning custom exhaust work later, headers give you a cleaner starting point than manifolds.

Do I need to ceramic coat or paint these before installation?

Stainless won't rust bare, so coating is optional. Some builders ceramic coat for heat management and a finished look; others leave them raw. If you go with coating, do it before install and let it cure fully per the coating manufacturer's specs.