Hotwire kit is not required. Its not a bad idea... but it isn't required. For what you're doing Mikey, a hotwire kit wouldn't be a bad idea with the procharger. I don't think you'd have any issue whatsoever with the stock wiring on a plain old 408. But with the procharger, it's a good idea.

Wire size is the restriction. The upgraded wiring only allows the pump to receive more voltage. More voltage = pump can work a little harder. It is not however going to start a fire like some people think...