Will this hose handle boost pressure or just coolant flow?

This is rated for coolant and water circulation in high-heat environments. If you're running it on a pressurized intercooler setup, confirm your system PSI matches silicone hose ratings — most handle 30+ PSI without issue, but verify your specific application before install.

Do I need hose clamps, and what size?

You'll need clamps to secure both ends of the elbow to your hose barb fittings or ports. Clamps are not included — grab stainless steel worm-gear clamps sized to match your 1.25" ID hose for reliable grip.

Can I use this straight out of the box, or does it need prep?

No prep needed. Silicone hose ships ready to install. If you're replacing an old hose, flush the cooling system or intercooler loop first to avoid debris blocking the new line.