Should be careful when checking coilpacks. the way Snozzle mentioned, may blow the coilpack driver (the box that sits at the end of the head).
If you can get to the injectors, diconnect them one at a time to see which cylinder it is. Much safer option unless you know how to check the coilpacks properly.
I would recommend splitfires, never failed on me once with 1.1 gapping and lots of boost.