What is Needed for a Tune-Up of a 99 Dodge Intrepid
 

A friend of mine has one and is doing her tune up(hella late it's at 150K miles :p). She just put spark plugs in and that helped out A LOT. She is now balancing and rotating her tires *shrugs*. What else needs to be done and about how much would this usually cost? I'm assuming the serpentine belt needs to be changed. She has the 2.7 btw.

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