When I bought my '00 in '05 with just 33k on the odo, it was a constant wheezer when idling w/ the squeal upon startup. Was very sure there was more that needed replacing than just the belts. Took it to my trusted mechanic and he only replaced the belts which completely restored the idling engine to what I would describe as brand new. All tensioners/pulleys were fine and did not not need replacing in my scenario. He explained that it is the sides of the belt that make the most contact w/ the pulleys...not the underside/inner surface.