You can use two fluids for your ZF 6 spd:
LifeGuard6 which is also know as Shell M1375.4 or
I sent new samples to Blackstone labs of these two samples because Turkeybaster researched Mercon SP and came to the conclusion that they were the same. Blackstone's analysis stated that they looked like they were in the same batch except for color and smell.
I changed my fuild at 38K miles and will do it again at 75K miles. I just dropped the plug and refilled. No filter change and don't plan to replace the pan-filter since they are integral until 120K miles.
There is a reason my M3 vert ran well past 200K miles, fluid changes at regular intervals. Let me put it this way, if BMW considers this lifetime fill which now they don't but used to then why don't they warrant the transmission for a lifetime?
Now BMW states 100K miles is the change interval when before it was lifetime. Also ZF the automatic transmission builder for this transmission and virtually most BMWs recommends 50K miles not in concert with what BMW stated. Mike Miller of Roundel Tech Talk and Bimmermag also recommends 50K miles. The choice is yours, good news is that you have the intelligence to make an informed decision once your research is done.
My fluid at 38K smelled bad but LifeGuard6 smells bad new so no big deal there. It was dark in color again no big deal there since it is picking up clutch material and steel from normal clutch use. It is a very slippy synthetic AFT and appeared to still have a lot of life left in the 4L or so I drained and refilled. I do think the 50K pan drain and refill would have been fine in my case. 60K miles? Probably not an issue...