Do I need hose clamps to install this?

Yes. This hose ships without clamps — you'll need to source your own T-bolt or spring clamps to fit your inlet and outlet diameters. Most builders use 2.75" and 3.00" clamps respectively.

Can I use this on a coolant line or just boost?

This silicone handles both. Temperature and pressure ratings aren't specified in the product data, so test-fit on your system first and confirm your specific cooling or boost pressures are within typical silicone limits before committing to long-term use.

How durable is 3-ply compared to 4-ply?

Three plies is standard-duty for most intercooler and turbo applications. If you're running extreme boost or sustained high heat, 4-ply offers more margin — otherwise 3-ply will handle normal street and mild track use without issue.