Ok, I'm ready to get a smaller pulley / tune for my 03 Cobra. Is the Diablo Predator and 2.81 pulley a good combo. I also want an additional idler pulley to wrap the belt around the smaller blower pulley. Which 2.81 pulley and idler pulley is best and how do I know what length of belt to get once I get a good idler pulley. Is there a place for one stop shopping for this stuff online? I don't want belt slip and want a safe tune. Thanks for any help guys.