I used one called "It's a snap"
http://www.itsasnapwireandcable.com/I completely re-wired my whole truck with it. The wires are marked about every ft so it's easy to identify them and they use the same color code as GM. They give you way more wire than you need to reach where you are going - so no splicing needed. I went with the larger one because we were adding power windows and a/c.
