I'm deleting my original post - I took another stab at my 986 plug change in the light of day and wanted to post some tips to keep with the spirit of this topic:
The KD Tools spark plug sockets (mentioned in a earlier post) worked perfectly for the 986 engine. I used the 11" socket for the 4 rear-most plugs and the 6" for the front 2 plugs. They are worth their weight in gold - no more trying to retrieve a lost socket deep in the engine. The only negative was that the hinged shaft on the 6" requires far more turns because the hinging reduces the effectiveness of each turn.
Plan on removing the wheel well liner held in place by two 5mm plastic nuts - it'll give you much more access to the cramped space.
You'll need to remove the 5mm bolt holding the spark plug connector wires in front of the 2 front-most plugs to get the wire & harness out of the way for full access to the boot and plug.
You'll also need a Phillips head screwdriver to remove a screw holding a u-shaped drain/vent that blocks access to the 5mm hex bolt on the middle plug on the driver's side. If you remove one screw and loosen the other, you can swing it out of the way to get access.
Just about the only tool that will reach the front-most (driver's side) 5mm hex bolt is a traditional 90 degree bent hex wrench, like the ones that come with furniture. Between the body & a very thick hose (or wire), you won't be able to use a hex socket, a foldout hex or any of the elaborate socket extenders and thumb wrenches I tried. You might get away with a low profile 1/4" mini socket or GearWrench type socket. This might not sound like a big deal, but owning multiple hex socket sets, and several folding hex sets, I never bothered to buy the 90 degree hex wrenches and had to run out to get a set to complete the 6th and final plug - very annoying!
Also, and your experience may very, but I found the 5mm hex bolts needed a fair amount of force to "pop" them and then they were easy to turn.
I had Beru plugs from the factory and found some of them to be very tough to get out. Two required maximum torque to get them loose and all were very tight and even "gritty" for the first 5 or 10 turns. I have changed plugs on at least 6 other cars (mostly European) and never had this much difficulty. I don't know if it's the whole "no anti-sieze" thing or what, but it wasn't very comforting and I was very worried about stripping the engine threads.
With the 11" extended socket, I was able to use my torque wrench to snug the plugs to Bosch's 21 ft/lb recommendation for the 4 rear-most plugs. I wasn't able to get enough room to turn the torque wrench in the front of the engine, so I just tightened them by hand to what I felt to be the right torque.
Allow plenty of time (at least an hour) to change the plugs because it's so damned cramped and even with a good worklight, you have to do a lot by feel. If you've only changed plugs in a front engine, you're in for a surprise. I used to think it was a pain to change the plugs near the firewall in my BMW because it was tight...
I hope this hellps fellow 986'ers out there. It's a pain, it's dirty, it takes while, but it's not too hard and I'm sure you'll save a ton over what the dealer wants to charge.