I wish a curse of locusts on whoever engineered the six motor into the Xterra.
For those of you who have already replaced your plugs , this post is old news to you. Even with the help of previous posts on the subject, this job is still a royal pain. The #6 plug is a totally blind procedure. The combination of extensions and a flex joint is mandatory but it requires a small hand (or bloodied large hand) to guide it on to the plug. Surprisingly the new plug went in easily. However guiding the wire on to the plug is also a blind operation. I replaced the plugs with NGK Iridium and new NGK wires. The new plugs are a noticeable improvement in start up and smoother acceleration.