Read all the way through this thread
http://www.zpost.com/forums/showthread.php?t=771325. The gap for the plugs on the n52 motor is 0.043 not 0.032 like on the M54's. When I checked the gap on my new PLZFR6A11S plugs they were all within .001 of 0.043 out of the box. I installed them that way in my 3.0si and everything runs fine.