I recently purchased the Zeitronix ECA Gauge, which is a combincation of a flex fuel sensor, a wiring harness, and a custom gauge. This gauge will also emit data (E85% and also Fuel Temperature) for logging if you have that capability, but as of this post Cobb has not yet enabled any type of flex-fuel tuning. Hopefully soon they’ll enable this function, as EcuTek already allows flex-fuel tuning!
I decided to install the gauge inside the fuse door, which is located near gas door unlock. It fits perfect, although it will cover up your fuse diagram. I took a photo of the diagram before for future reference.
As for the wiring, its about as easy as any other gauge. Just hook it up to a switched 12v connection, a ground, and connect the signal cable on the harness and the gauge. Thats it!
With the increasing amount of high horsepower Subaru’s running around, being able to monitor the quality of your fuel has never been more important!