I got back the JK two days ago from the head replacement and it most certianly picked up some power. It runs quite a bit better and I cracked off 20.5 mpg this morning (according to the computer) on the way to work. That is 2 mpg higher than normal.
Overall, the dealership did a great job and it only took three days to complete.
All is forgiven Jeep. Other than this issue, 19k miles of flawless performace.
Future: '18 WK2 or a JL
Current: '97 ZJ - Lots of mods
Past: CJ-7, XJ, KJ, JKU