My only suggestion would be to swap out the Nismo Exhaust you want for a Fast Intentions exhaust instead. WAY better sound and better gains. Probably much cheaper than a Nismo Exhaust too
Also, I have heard the EcuTek (which is what I have) is slightly better than UpRev. Probably can't see any obvious driving differences but it has more updated software and a few more custom MAPS than UpRev, again could be wrong but I wanted to throw that out there for a good debate.
Lastly, not sure why you want a Tranny cooler, totally cool if you get one but i have a lot of Z friends, who track quite often (including myself) that are not FI and their Trannies stay strong.
Final thought: if you choose to go Fast Intentions Exhaust (money saved) and not go with the AT Cooler (money saved), use what you saved and get better rotors, pads and Dot4 brake fluid OR instead do sway bars or something suspension wise.
Cheers to whatever you choose
Happy Modding!