I realize this is an old thread, however I thought I would include me two cents having just replaced my EGR valve 30 minutes ago in my drive as snow was blowing around (thats right, friggen snow May 12!) Anyways, this job is actually very easy and you really really do not have to remove your upper intake or plug wires.
In fact all you have to do is (assuming you are working on a 3.8L not a 3.6L engine):
1. Open your hood, with a long flat screw driver unplug your old EGR valve
2. Remove your RF inner fender
3. Remove the EGR to intake tube bolts (8mm socket, extension and ratchet) and discard old gasket
4. With a shallow 10mm socket on your ratchet reach in behind the EGR and remove the two bolts securing the egr to the engine, discard the old egr valve and gasket
5. Clean all old gasket surfaces making sure all old gasket material has been removed
6. Re-install EGR in opposite order of removal, clear engine code or remove negative battery cable for two minutes.
This procedure will take you around 30-40 minutes depending on the size of your hands/ mechanical ability, I highly recommend doing this job yourself as there is very little about this job you can screw up, I also really suggest NOT removing your plug wires or upper intake as some service manuals (all data, OnDemand) may recommend. Removing your upper intake will require further parts and you may induce an intake leak if you do not reinstall correctly. The upper intake is not a very large job but why do work that is not necessary?
Any questions feel free to ask! Keep in mind this short write up is for the 3.8L engine not the 3.6L