as above, make sure the engine is proper warm before starting, take it for a good 20min blast to get everything toasty.
i did mine when they were proper hot, on first attempt they didnt budge (torque wrench set to 30nm), sprayed some WD40 down the edges at the thread and they popped right out.
also as stated, do the controller at the same time, i didnt and still have glowplug issues, so i think mine is dead
