Ecutek + FF is probably the best route if you want top tier NA performance without any concern for MPGs.
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MPGs will go down drastically from my experience, but may not be an issue for track cars etc.
You'll get more power not doing FlexFuel & run something like an Edelbrock SC. Similar MPG loss, but much more power and you can fill up anywhere.
Like everyone has chimed in with, very limited locations to get E85 here in PDX, if there was a spot easily accessible on the westside (Beaverton-Hillsboro) I would be tempted to try it out again to really feel 2-5mpg with the SC
