Hi Keith,
I had the first ever RHD twin turbo 370z in the world back in 2014, which happened to be a 7AT. Unfortunately the UK tuner that did the mapping didn't have a clue on what he was doing and damaged my gearbox, while lying through his teeth.
I had to rebuild it in USA by our partners at Level10 and also fitted an uprated torque convertor, did the valve body upgrade, all internals overhauled, making it capable of 700+ bhp.
Going back to your build, with the right mapping on ECUTek you can safely run a supercharger or a GReddy Twin Turbo. There are so many guys in USA doing this with no major upgrades to the gearbox. We also have a customer here in UK with a TopGunz supercharger on his 370z, the only upgrade to his gearbox was this:
https://www.torqen.uk/nissan/350z/powertrain/transmission/67065-350z-z33-370z-z34-loj-conversions-billet-aluminum-flexplate-vq35hr-vq37vhr.html
Hope this helps, let us know if you have further questions.