This is pretty much the same procedure for changing the transmission fluid (partial change) in an X5, which is rated to 100,000 miles. Why the M3 DCT is "lifetime" while the X5 is 100k is beyond me.
Any suggestions as to when you think the fluid ought to be changed?
Also, could you elaborate a little on how you measured the fluid temprature? Is it as simple as inserting the sensor into the fill-opening?
Thanks for making this thread!