This might be a good excuse. I suggest the following:
ZZP SC coupler
ZZP oversized idler pulley
2.2" Pulley Boys SC pulley.
The coupler will fix the SC rattle, the idler, since you have to change it anyway, goes very well with the smaller pulley. Otherwise, go to your local auto parts store and get a new idler pulley. They're very inexpensive. Just remember that you have 2 idlers. 2 belt system.