I just did my second fluid change with MaxLife in my BMW 328i with the GM GA6L45R. I changed the original factory fluid at 40k miles with the MaxLife and the shifting improved immensely. The transmission felt much smoother and didn't seem to jerk between gears at lower speeds like it had done before. I changed the fluid, then drove around the block and changed both the fluid and filter. Now 30k miles later (I just hit 70k miles) I just did two drain and fills. I highly recommend the MaxLife in these GM transmissions, and I don't drive this car like grandma. It sees wide open throttle at least twice a day. I hammered the snot out of it several times on tail of the dragon in TN right after the initial fluid change at 40k, and when I changed it just now at 70k the fluid didn't even look dark.
I originally chose this fluid because there is a guy on the BMW forums with the same transmission in his E91 328i wagon. He tracks the car frequently, and his transmission has almost 300k miles on it. Maxlife is what he uses.