Try and clean out the plug recess first with air if possible,quarter turn spray a nd leave for 5 mins sometimes the plug actually tightens as you remove,electrolisis can cause this and if you wash your car regularly the water goes straight into the recess and then burns off leaving a resedue.Because of where the plugs sit on the duratec and if you use the car in the rain i would whip them out once a year, duratec owners will be shocked at the outside state of the plugs although working ok water goes straight through the louvres and down the plug hole.Dont panic it wont be cross threaded just tight.
Em
