Motorcraft plugs seem to be the plug of choice for the money.
I put a thread up a week or two ago on Group A coils, have a look in there and let me know on the thread if it makes much difference.
https://passionford.com/forum/viewto...ighlight=group
https://passionford.com/forum/viewto...ighlight=group
https://passionford.com/forum/viewto...ighlight=group