Do I need clamps for this hose?

Yes. You'll want hose clamps at both the inlet and outlet to secure it to barbed fittings or ports. Silicone alone won't hold under pressure or thermal stress.

Will this work for coolant or boost lines?

Both. Silicone handles coolant loops and intercooler piping equally well. The 3-ply rating supports typical boost and cooling system pressures on street and moderate track duty.

Can I use this to replace a kinked factory hose?

If your old hose routed in a 90-degree path, this reducer is a direct swap. Test-fit first to confirm the taper and angle match your ports before securing with clamps.