Thanks MikeC, for you understand electrical components when in use on an auto.
The best way to kill an electrical circuit is to cause it over heat. One of the best ways to overheat a circuit is through poor wire, either too small or poor conductor, kinks, cutc, knicks, and poor connections. Improve any of these, and you'll increase the reliability of said circuit, and make the circuit preform better because the electricity isn't working as hard. Same reason why people add intakes and exhuasts....it puts less strain on the engine making it more efficient and work better, ie, more performance.
LB, while the "spec" electrical system would work, there's no use in causing premature component failure, or an unsafe situation. Good vehicle grounds and hots, depending on just how much you want to add, wouldn't be a bad idea to upgrade.