Will I need new exhaust piping downstream of this header?

Your existing exhaust can stay, but you'll want to verify the outlet diameter matches your current piping. If it doesn't, you'll need transition piping or a custom downpipe to connect cleanly.

Do I need to tune after installing this header?

A tune isn't required to bolt this on, but your engine's fuel mapping won't be optimized for the improved exhaust flow. You'll see better results — and may prevent a check engine light — if you get a tune or tune file loaded after installation.

What do I need to do before installation to protect the header?

Inspect the mounting gasket surface on your engine block for debris or corrosion, and clean it with a wire brush. Use a high-temp gasket sealer on both sides of your new gasket when bolting the header down to prevent exhaust leaks.