i have the 2002 V6 and i did the rear plugs on mine. I would do it again to save $400 but most will not find it a pleasant job, i didn't.
I did NOT remove the plenum. On a car this old my advice to you is, its better if you don't either. (Not o nly will it cost you more for gaskets and etc. but theres a real risk of the gaskets not resealing right - THEN WHAT? you have to do it all over again.)
There are several posts here on how to change the back 3 plugs, i'd read them all. Here's some additional advice,
-wear rubber gloves to protect your hands. buy a box, you'll need several pairs.
-use masking tape to hold sockets and socket extensions. Also when you put the spark plug in the socket use one piece of tape to hold it in, that will easily tear once you have it started in its hole in the engine.
-use high temp anti sieze on the plug threads, because you know you are not doing this again anytime soon hopefully!
-set aside plenty of time for this job. count on two to three hours or even longer. it may not take you this long, but this is not a job you want to rush.
-job should be done with engine cold. you are going to need to climb on and actually, practically hug the engine to access the back plugs so plan it so that engine will be cold. Also find two old towels or blankets for fender covers, you are going to be leaning on the fenders for a significant period of time and why scratch up the fenders.
-i bought a special tool for this from harbor freight, it is called sidewinder wrench. It has a handle on the end of the socket handle that allows you to turn the socket without pivoting the socket handle. hard to explain with out a picture
http://www.harborfreight.com/cpi/cta...=112&zmap=4432
but this tool cost me $10, 3 years ago, its now $25 and worth every cent. You want the 3/8" model, i found this tool invaluable in getting the middle plug out.
Don't give up, you can do it and change these 3 damn plugs, but you probably wont find it easy!