Ideler Pulley (sp?) out. how much do those run?

 

Not at all, they rotate.

 

PPl say you need 1 when you Change your other pulley. Unless you have a Bigger stero in your Car or other itmes taking power from you car. Yes you will Need it other then that you should not you Car will allways stay in a Open LOOP. at idle. Btw you can get a nice 1 for like $100 if you really want 1