Just dawned on me that the G35X that my wife drives might need new plugs as they have not been checked since we purchased the vehicle some 8 or 10 years ago. When you look at the attached photographs, it is clear that they are very difficult to replace and apparently nobody
did. I would say that this is what twenty year old plugs look like. You could throw a cat through that gap in the electrode. Must not matter very much on the vehicles as it still ran great.

I would highly recommend that you do not remove the coil electrical connectors unless necessary as they are difficult to reconnect with extremely limited space.
Regards.

 

Not sure what you mean about difficult on the HR engine.. It's not a Jaguar V8 with no room to spare and i'm just surprised that your G was even starting..
I only detached the intake pipes and had access, a 10 minute job..
I ran NGK Iridiums in mine and had no issues but no matter what, it still made an awesome 14 mpg average..

 

What year is your G35? Mine is a 2005 and I thought the plugs were at least fairly difficult to replace with my gigantic hands (which never helps). On my G20 they truly take 10 minutes. Have you ever replaced your timing chain? That is my next task.

 

OP, your 2005 is a VQ engine. Single intake. The HR is its successor; it has dual intakes, among other differences.