I’m not sure where this thread is going, but in a nutshell, it has to be proven that the aftermarket part caused the warranty claim. But … the biggest factor is the dealer you take the car to for the service work. Some dealers here in my area actually install exhausts and lower cars before they are even sold. It is really up to them to interpret the warranty claim. For example, I have taken my lowered car to an Infiniti dealer to get an upper control arm checked out and they were cool with it. You just have to know who the mod friendly dealers are.
IMO, get the oil cooler if you need it for the way you drive your car. But I think asking Nissan to change their design will not be possible if the car functions as it was designed to do. We simply cannot argue that because the Z is a performance car, it needs better cooling. Imagine if that were the case … everyone would be TT with 500+ WHp.
That said, if you are tracking your car, you do so at your own risk. If they are able to prove it, they can and most likely will try to deny any warranty claims. BTW, Isn’t this what all the GTR owners are pissed about?