Do I need new gaskets when I install this?

Yes. Factory gaskets compress and won't seal properly a second time. Grab new header gaskets before you pull the manifold off — makes the job cleaner and eliminates exhaust leaks.

Can I reuse my existing exhaust piping and catalytic converter?

Depends on your setup. The header outlet diameter may differ from what your current exhaust uses, so measure before ordering. You might need adapter tubing or a new downpipe to match.

Does this need paint or ceramic coating?

Stainless won't rust bare, but heat cycles will discolor the metal over time. Many builders leave it raw for that industrial look, but you can wrap it or apply high-temp coating if you prefer a finished appearance.