Do I need to use a gasket between the header and manifold?

Yes. Header gaskets are standard practice to seal exhaust ports and prevent leaks. Check your service manual for the correct gasket type for the 3T-C — it's not included with this header.

Will this bolt directly to my stock exhaust system?

The header bolts to the engine at factory mounting points. Verify your existing exhaust piping diameter matches the header outlet before purchase — you may need an adapter or replacement piping to complete the install.

Should I polish the stainless steel or leave it as-is?

The header ships ready to install. Stainless doesn't rust, so polishing is cosmetic preference only. If you want a mirror finish, use stainless steel polish after installation — avoid abrasive methods that can scratch the surface.