Changed the spark plugs on my 2016 3.5L last week. Noticed slight roughness at idle, decrease in fuel economy, and a little lose in power. I have read that the ecoboost motors are hard on plugs so decided to change them. Hardest part was getting the coils off. Learned (the somewhat hard way) the best place to pry is on the screw hole. Truck has 48,XXX miles on it and the original plugs did not look great once I removed them. With the new plugs the truck is back to being it its old self.
Reminded me of working on older cars a bit as I could actually get to the plugs pretty easily without removing half the engine and performing extensive yoga maneuvers.