I would not go with those plugs. The Duratec requires double-platinum plugs and anything less will wear out very quickly. I had a set of platinum plugs wear out in about four months. A few people have had success with NGK Iridiums or Bosch +4 plugs, but many others have had problems.
Autolite makes the OEM Motorcraft plugs for Ford, I don't know the Motorcraft part number, but the Autolite is APP764. Plugs are relatively cheap, so try what you want, but if they give you problems switch to the Autolites.
