I have used Amsoil and Motul... Probably amongst the top 3 for choices. I didnt notice a difference in one vs. the other but the motul was a little more expensive.
The Differential calls for GL5 oil where the manual trans calls for GL4.
Check the link below its direct from Amsoils site. They were the FIRST in synthetic oil and their stuff is great! I used in my engine, trans and differential and put in all my other cars as well!
AMSOIL Product Recommendations - 2010%7cNISSAN%2fDATSUN%7c370Z%7cM