Do these hoses need prep or finishing before install?

No prep needed. The blue sleeves ship ready to route and install as-is. If you're cutting them to length, deburr the cut end with a file to avoid sharp edges inside the line.

What diameter and length do these come in?

These are universal-sized hoses — you cut and route them to match your application. Measure your run before ordering to confirm this set covers your routing distance and circuit needs.

Can I use these for fuel, coolant, and brake lines?

Stainless braided hose handles all three circuits. Confirm the pressure rating matches your system before commit — fuel lines and brake circuits have different pressure specs than coolant loops.