I hope you dont break spark plugs when changing them.
My buddy changed 5 of his without issue. That 6th one tho cost him $6400 for the cab to be pulled and remove the driver head and all that fun stuff.
Apparently the threads protrude into the chamber and get carbon up. On removal the carbon turns to a thread issue and it turns ugly.

 

I had a 2007 Mustang with the 4.6 3v and those dreaded plugs and managed to get them out with no issues.

I changed my plugs already when I did the tune.

 

Cool. I remember him saying even when they are stock the tech told him to change the plugs every 30k miles if he was towing the camper. And 50k miles just normal daily driving.
If it was tuned and turned up a pretty good bit then change them sooner.
Also W/M injection helps keep everything way cleaner inside.