I'm interested in this thread with me just bringing home a 24 BRZ. One thing I've seen is that the higher viscosity Motul gear oil use had caused hard shifting in cold temps, it worked well when warmed up but was harder to shift in cold temp first start up use.
I'm considering going with Redline MT-75 or possibly Amsoil MTF (5w30), but this new Motul seems interesting if it is now available, I don't want to use their gear oil, I prefer a dedicated MTF type of fluid.
I switched to redline MTL (75w80, so same viscosity) and I like it much more than gear power. Next thing I am going to try is Ford motorcraft.