When wiring a progressive, which wires are the main ones to be concerned w/ as far as interference?...the grounds to the solenoids? The 12v activation?

I've always heard the Edelbrock controllers are REALLY sensitive to interference, but work great. I'm just using an older 2 dial controller for now, but really like the Leash products I've used in the past (on other people's cars) and will most likely end up getting one of their controllers when funds allow.