I will be switching to M1 0w-40, for the Z.
It has proven itself to be a solid oil based off of strict UOA testing. Its also relatively inexpensive and readily available.
Quoted from UOA thread…
Mobil1 0W-40- A thicker oil with really good to average wear results combine to make it a versatile oil for the daily driver and those who do track days as well. Will hold up well for extended oil change intervals and can be used in any climate.