i have a PIH kit in my stang but i got it back when no one was tuning our computers (at least around here).
i wouldnt call it a waist if you can pick one up cheap and i realy love the manual fan controler in the old kits. it has full on/off setting for low and high speeds of your fan.
now adays i would just get a tune unless i found a complete PIH kit for dirt cheap but with enough mods you'll still need a tune with the A9L/A9P