The car is built with modern sensors (crank position, knock, iat, etc.) and using an ems so detonation won't be a an issue because we have full visibility and control over fuel and timing. It's going to be mostly a street car so full alchohol isn't desirable due to the things we've mentioned here.
Running a flex fuel sensor for e85 was just an easy, cheap way to be able to get some extra horsepower when e85 is available. The sensor was $50 and once the car is tuned I can mix and match any volume of 91 gasoline and e85 and the ems will automatically compentsate.