Do I need gaskets or fresh hardware to seal this to the manifold?

Yes. Use a quality header gasket set rated for your engine. Bolts and fasteners are not included — gather hardware before install to avoid breaks on removal.

Can I install this myself with basic hand tools?

Shorty headers bolt directly to factory points, so no cutting or welding is needed. You'll need a socket set and gasket scraper. If you're comfortable removing and reinstalling the stock manifold, you can do this job in an afternoon.

Does the stainless finish come ready to bolt on, or do I need to clean it first?

The header arrives ready to install. Inspect the gasket surfaces for debris and wipe clean before bolting down to ensure a tight seal.