Will I need to replace the header bolts when I install this?

The bolts can be reused if they're in good shape, but if you're pulling the header, it's smart to grab fresh fasteners — they handle heat cycling and can lose tension. Check yours before you button everything up.

Do I need to prep or clean the mounting surfaces before install?

Yes. Scrape off any old gasket material and carbon buildup from both the header flange and cylinder head. A clean, flat surface is what makes this gasket seal properly.

Can I reuse the old gasket if it still looks okay?

Exhaust gaskets compress permanently under heat — once they've been torqued down, they won't seal the same way twice. Install fresh every time you pull a header.