Firstly to the forum.
You appear to be struggling to get an informed diagnoses and as you already know guesswork can be very costly.
My advice would be to get the car on Consult at a 350Z specialist to pinpoint the issue.
Is your car an Auto or 6 speed manual and what is the mileage?
Alex.
So what ones do you want, 800 or 810?
Also how many do you want, 16 or 20?
Do you also require the lug nut socket?
Are you fitting these to LMGT4 wheels?
The solution is to use preassembly grease.
There are circa 80 x 6mm similar bolts on the R35 GT-R undertray panels and every time I have them off I always re-grease them which is very time consuming but well worth it.