I just changed mine in, front ones are a breeze, rear ones aren't that bad, once you get that valve out of the way!
The 2 short extension method was the easiest for doing the rear plugs, slide the plug socket and one extension in then attach the other extension, get them on the plug, attach the socket and crank away.
I did learn the hard way about installing the bottom nuts on the flange, drop one, grab another one and drop it too.
I found some more flanged nuts and then smartened up, wrapped the socket with the nut in it with a bit of tape and it worked out perfectly.
Made sure to use anti-sieze on the plug threads, whoever did them last didn't and I could feel it when I was removing the old plugs.
Seems too logical, if spark plugs are going to stay in the engine for around 100,000 miles then why take the chance, especially in aluminum!