Do I need clamps, and what size should I use?

You'll need hose clamps to secure both ends — the hose itself does not include them. Measure your barbed fitting diameter and go one size up; a 3.00" hose typically pairs with 3-inch or 3.5-inch clamps depending on your adapter size.

Can I use this on a stock cooling system, or is it boost-only?

This hose works for both. It's rated for high-temp coolant and vacuum lines as well as forced-induction applications. If you're replacing a collapsed or kinked factory hose, this is a direct upgrade.

Will this fit my existing adapter fittings?

The 3.00" bore is a common size for turbo outlets and intercooler connections, but test-fit your fittings first. Some adapters use slightly tapered or compression-style barbs — verify the barb diameter matches before finalizing your order.