Do I need hose clamps to connect these pieces?

Yes. These are bare aluminum fittings designed to work with standard worm-gear or band-style clamps. You'll need to source appropriately-sized clamps for your 2.5" hose diameter.

Will these pieces need any prep before installation?

The black anodized finish is ready to install as-is. If you're painting them to match your engine bay, degrease with soap and water first, then sand lightly with 220-grit before primer and paint.

Can I test-fit these before permanently sealing everything?

Absolutely. Test the layout with clamps hand-tightened first. Once you've confirmed the run, tighten clamps fully and torque according to your clamp manufacturer's spec—typically 4–8 ft-lbs for worm-gear clamps.