You are rough on the coils and spark plugs. You shouldn't be using an impact drive to remove the spark plugs, they can break inside the head then you'll have a bigger problem. They should be removed by hand with an extension and a 5/8 spark plug socket.
In my experience, as long as you break the spark plugs loose by hand, and turn them a few times, you are perfectly fine to remove it with power tools. I do it to save my wrists. Seen to many people get carpal tunnel. Same thing going in, set drill to slip easily, run the plugs down and snug them by hand.
