Will these headers fit with my stock exhaust manifold gaskets?

Stock gaskets may work initially, but stainless headers run hotter and last longer than manifolds — pick up quality performance gaskets rated for headers to seal properly and avoid exhaust leaks down the road.

Do I need to upgrade my exhaust piping, or can I keep my stock downpipe?

Stock downpipes bolt up fine, but headers flow better than factory manifolds — pairing them with a performance downpipe unlocks the full benefit. Stock will work, just won't maximize the flow gain.

Will the stainless steel discolor or need polish to stay shiny?

Stainless resists rust but will develop a natural patina from heat — the tubing stays structurally sound. Polish occasionally if you want mirror finish, or leave it as-is; either way, no rust problems like mild steel headers.