The [COLOR=red ! important][COLOR=red ! important][/COLOR][/COLOR]electrical resistance of a wire or circuit is a way of measuring the resistance to the flow of an electrical current be it AC or DC current. The larger the wire diameter and composition of the wire the less resistance. This being said; if you have a copper core spark plug wire you will have less resistance in the wire than say a carbon core wire but you will have more RF interference. The RF interference causes problems with today's computerized vehicles so we must use larger diameter carbon core wires.