My wife and I have both had this issue in the past on my 370z and her 350z. It was a nightmare to get off when needing to put air in the tyre. As above best off sticking to standard caps I am afraid.
Cracking video's buddy. As above whats next? I have loved both of my zeds and will probably be back in 1 in the future, but my V8 itch has gotten too much to bear so I am scratching that itch whilst I am able to
I would imagine it would be something stupid like £8000 as they base their assessment on a standard car. then lowball you when you go to visit them....