Well its pretty time consuming to pull a head.
If they won't even try a new coil pack before pulling the head then there is something wrong with them. Try the easy things first. Go to a different dealer and tell em the entire story and see what they can do for you. I know I would have started with the plug and wire, then moved onto coil pack, then check the wiring harness that runs all the way to that coil pack. If all is good, then check the injector flow rate. I couldn't imagine needing to pull a head or even more for a misfire