Do I need hose clamps to install this?

Yes — clamps are not included with the hose. You'll need appropriately-sized stainless steel or worm-drive clamps on both ends. Size depends on your system's connection points.

Can I use this hose with my stock coolant system right away?

As long as your existing connections match the 4.00" diameter, you can swap it in directly. No prep or painting needed — silicone doesn't require surface treatment.

Is this hose pre-curved or does it come straight?

It ships as a straight section. You can carefully warm it with hot water to improve flex during routing, but test fit before final install to confirm clearance.