Do these headers require manifold gaskets or sealant before installation?

You'll want gaskets between the headers and cylinder head. The assembly itself doesn't include them — grab a set rated for your engine block to ensure a clean seal.

Can I bolt these to a stock intake manifold, or do I need to modify anything?

Long tube headers are a primary modification — they're designed to flow into a performance exhaust system. Stock manifold compatibility depends on your specific engine bay layout. Test-fit before committing to permanent install.

Will stainless steel headers discolor or need polishing after use?

Stainless resists rust and corrosion significantly better than mild steel, but high heat can produce a light patina over time. Appearance stays functional — no maintenance required unless you're aiming for show-quality polish.