Today I change out the plugs, as I wasn't convinced the dealer had done them, when I bought it.
Needless to say, more of a pain in the neck than my old 06' 3.0r Outback.
Airbox and battery out job, no way to do it from underneath.
The plugs have a 14mm hex, so you'll need a 8mm plug socket IIRC.
Coils are easy to get out though.