I shorten my servo wires all the time, I don't need 6" wire on a touring car when the receiver is less the 1" away. Same for the speedo.

The easiest way to shorten the servo wire is to find an extra servo connector, wire and plug. Open the servo and mark down where the negative wire solders on, the other two are obvious. Un-solder the stub that got torn and solder on a new piece of wire with the plug end already on. I find it easier to strip the wires on one end and solder on then to crimp new connectors on. If you dont crimp, you would have to solder a new end on which I think is much more work and looks sloppy then to open the servo and solder the new wire, at the exact length you need directly to the servo.

Good luck!