The Nissan spark plug # that I posted is an updated plug for these engines,it has the last 2-3 threads removed so threads are not sticking down in the combustion chamber where they can get carbon build up on them.
as for taking them out work them out SLOWLY....when you start to feel some resistance....turn the plug back in and keep working it in and out like this until removed,I Also use PB Blaster to help. I then use a spark plug tap and chase the threads to straighten them back up. Also there should be no need to use anti seize as the threads are nickel plated on theses plugs,but you can if you want your choice.