As wstar, and others have mentioned, there is a myriad of factors playing out here. Including that Nissan could have changed something that we do not know about in production. This means that certain model combinations as well as certain VIN numbers could be higher candidates for overheating. This is the reason documenting all matters we help us reach a better and faster conclusion leading to a resolution. What has yielded definitive results is that a properly sized oil cooler has solved the situation.
Having Nissan void a warranty because I installed an oil cooler is not a solution for me. If there are others installing an oil cooler, I would at the very minimum closely replicate or at least use the same Setrab oil cooler, or the actual Nissan oil cooler kit, should you end matters in a court dispute with Nissan. Nissan's sizing of the cooler core:
2009 Nissan 370Z Touring: Oil Cooler Install and First Service
If you are following the Edmunds blog above some of the most logical, and damning comments are those regarding the Sport Package option as you would think—at the very least—that the Sport Package would be inclusive of an oil cooler.