I need help choosing a plug for my truck. My current mods inlcude, nelson tune, K&N FIPK, MSD Wires, 160 t-stat, Borla Cat Back, and I will be adding my pacesetters, and y pipe with no cats when they arrive. What do you suggest? I know most of you are running the TR-55, do you think that would be my best choice? How bout the iridiums? Anyone have the actual NGK part number for either or both of those?