FYI I am advised by an Eastern states tuner that the stock
ecu can be open source tuned to handle flex fuel sensor by using the spare 3 fuel KCA tables and timing additive tables) and BRZ/86 done as well. Easy way was the O2 sensor heater element but the flex fuel sensor(either GM or Haltech) was easy to add in. Simple Sensor/Heater/Blended table determines which is used. TGV delete gives the sensor input wiring harness
The KCA High value adds a percentage of fuel when IAM is on 2.00, it halves the fuel added with IAM at 1.5 etc