To make a long story short, I need to replace the wiring in my 1970 coupe as the original harnesses has been butchered and I have all sorts of electrical gremlins. I was thinking of getting the American Autowire Classic Update kit 1970 Mustang. I'm still fairly new to mechanical work and haven't done too much wiring. My question is...How difficult is it to install one of these kits? Would I be making a mistake to replace all the wiring myself?