For stepper motors, use a stranded 20 or 22 gauge wire. If using home/limit switches, shielded wire is probably a good idea. I don't use switches on ine, I home it up to the hard stops. If you do this, make sure the machine is built tough enough to not tear itself apart. To use softlimits in Mach3, you will need to reference the machine position to a very repeatable place, or the softlimits won't be of much use.