SAAB makes a turbo'd car that runs on E85. That is actually tuned for it and runs faster on the stuff.
Maybe the emissions systems from this SAAB will transfer to the WRX? Since all the saabaru stuff, maybe? I dunno...just a thought. Have you looked into it?
Great FAQ btw. Its saved in my favorites. Contemplating getting a tune for 50/50 of this stuff.