After reading about this TSB, and truly feeling that my car was not running and performing as smoothly as a $36k car should, I asked my dealer to do the PCM update. Even though the "check engine" light was not on, they did the update as a courtesy to me. Well, the car now has better throttle response and a smoother takeoff and response through the gears (automatic). I like my XF much better now. Smooth AND good looking!