These aren't too bad to do. The 4.6L V8 has a coil-on-plug design which eliminates spark plug wires. To change the plugs, locate the coil(s) that wil be close to each cylinder's fuel injector, disconnect and remove the coil, and then remove the spark plug. They're pretty easy, albeit a little time consuming.
One thing to remember...If a plug doesn't feel like it wants to come out easily, don't reef on it. You'll break it off in the head! If you start to feel resistance, turn it back in about half a turn, then back out till it starts getting tight again, back in a little, back out some more, and so on till you get it all the way out. A good penetrating oil such as PB B'laster is a must-have if you run into one or more that want to fight you. Spray a generous dose of penetrating oil down the plug hole and let them soak for a couple hours, then go back and do them the way I described...A little at a time.
I definitely recommend Autolite plugs for replacements. They're identical to the OEM Motorcraft plugs, but cheaper and more readily available. Go with the APP series double platinums or the XP series iridiums. I wouldn't use a single platinum (AP series) or non-platinum (no prefix) plug in these just due to the lack of durability. There's nothing to gain as far as performance goes with the higher end plugs, but unless you want to change them every 30,000 miles, get a good plug in there so they last a good long while.
