Hey guys I have a 2.90 Metco pulley nib. I plan on installing this very soon. Will I need an AUX Idler, or will I be ok without it? I also have a 100mm idler pulley that I can install. So do I need a new belt? Or will the stocker be ok? Car has jlt ria, pypes x-pipe w/ metallic cats, Borla stinger, and currently tuned. Car makes 421hp currently and hoping to break the 475 hp mark after pulley install and retune. Thanks for your time.