If you can get one for MSRP I think the sport Z is a better starting point. Upgraded brakes, aftermarket wheels & LSD and you're probably still under the loaded 2.0 price tag.
Base vs base boils down to if you want a nicer interior or two cylinders. The good old American mentality of bigger is better leads me to believe the latter will be more popular in the states.
Another review... people are saying Sport is 39,990 and Proto-Spec is 50k.
https://www.nissanzclub.com/forum/threads/spanish-the-new-2023-nissan-z-launch-control-revew-what-a-car-dani-clos.1126/
There was some online chatter that only the US will be getting the manual, but it's also listed on Canada's press release.
http://media.toyota.ca/releases/toyota-gr-supra-adds-manual-transmission-and-enhanced-drive-dynamics-for-2023
There only have been hand full of leaks via dealers. There could be more, but the top two I can think one was when someone had leaked 6th gen Camry from a dealer meeting and more recently when a dealer had leaked images of the 3rd gen Tundra.
No doubt the Z has a huge fan base. They're going to sell good in the first few years. The real question is will Nissan give it proper updates to keep sale numbers from tanking as seen with the 370Z.