I need an alternator for my 2002 S60 non turbo non AWD. I went onto the FCP website and there are 8 different ones for my car. I think I need the 120 amp one, but there's a "with freewheel style pulley" and another "without freewheel style pulley". How do I know which one I need? I called them on the phone but the guy on the phone was unsure too. I also need the alternator belt tensioner, and should probably get the belt itself while I'm at it. Any help would be greatly appreciated.