Like I mentioned in another thread, half of your plugs will fire backwards. Ford may have seen this as a potential durability problem and put different plugs in the cylinders that fired reverse. A double platinum plug on all the cylinders will work fine. Otherwise, go with an iridium plug like I used, the Autolite XP series (XP103 if it's a V6.). They are even more durable than a platinum plug, and iridium conducts electricity better than platinum. I'm very happy with mine...Not that I wouldn't have been with double platinums, but these work great and weren't much more than the double platinum APP series plugs.
In case you didn't know it...Autolite and Motorcraft plugs are identical. Autolite makes Motorcraft plugs.
Edit: Though I don't remember the original part number, all 6 of mine were the same when I changed them. I'd assume they were original based on the wear they had at ~70k.
