take both pulley to a trustworthy auto shop other than your dealer. several forumers have had problems with their dealers, and not just about aftermarket stuff.
Problems with RRM Light Weight Pulley
So I've taken my koup to the dealer and had the idler pulley replaced 3 times for a loud squeak/squeal underneath the hood. The dealer said, after the squeaking/squealing would not subside, that it was my RRM pulley that was the culprit and that they needed to replace it with the stock one. I took my koup up there today to do the swap, and not only did the service manager say they've got it and it was no problem to swap it out and see if it changes anything then charged a Benjamin to do it, the squealing/squeaking hasn't sotpped. Has anyone encountered a problem like this? and is everyone's service manager against anything aftermarket on cars? 
