i used scotch locks... as long as you make sure you squeeze them tightly with some pliers, to make sure the "pin" punctures both wires... jobs a goodun. a friend of mine does that and then cable ties them shut to "be sure"
i took the gauge to my local motor factors when sizing the pod, and they just cut me lengths of red wires which i marked up when extending
i also used fuel lines when running the boost pipe for a more OEM look under the bonnet.