[samuelso]

I did my plugs myself (2GR-FE) and will echo what everyone else has said here. Make sure that you get 3 new plenum gaskets (17176-20020) and the throttle body gasket (22271-0P020), and clean the throttle plate and MAF while you have everything apart.
I would also recommend that you consider having at least 3 coil wire plug harnesses on hand. I found that mine were very brittle and sort of disintegrated as I was removing them from the coils. The housings are available separately (90980-11885) but that requires you to do some significant surgery while contorted (at least it did for me). You may want to consider getting some which have the wires already attached and splice them in a convenient spot.
The biggest issue I had was dealing with the passenger side rear plenum bolt. Getting it in and out is a real pain (you have to work 'blind' by feel, and it is a very tight squeeze to get a wrench on it as there is a large bundle of wires interfering with the access). I found that if I tied a piece of fishing line to the bolt, I was able to drop it (about 50 times) into no-man's-land and still retrieve it to try again. Good luck!