Honestly, with that kind of money floating around you could have gone to the stealership and 'dare I say' still would have come out ahead... at least in that situation you buy complaining rights to Nissan of NA to get it done right.
With Z1 having no warranty on any of their work is sending all kinds of red flags in my opinion. Why have a service department and not be able to back the work all the while claiming to be the experts...
Now, I guess it is nice that they tell you on the form they don't back the work but before signing it I would've walked away... lol.