Update on this thread. I worked with my tuner to get the ECU firmware read out by the Woolich software. After some minor tweaks, we now have full access to the ECU.
I also spoke with a BMW race engineer about data acquisition. The M Datalogger and GPS Laptrigger kit will provide all necessary data, including potentiometer readings (stock harness has plugs). This can then be loaded into 2D software along with MotoSpec math channels for more precise chassis/suspension telemetry and tuning.
Hope this helps some people!