I was able to make 699rwhp with GT500 pumps, a single 40 amp bap, and 970cc Bosh injectors with E85.
The pumps were just about maxed but it all worked. I also was using an 8 gauge power wire and all stock fuel lines.
This was with a D1 Procharger and built 4.6 motor with 11:1 compression, stock crank, FRPP heads, 127400 cams, and stock cats.
I'm of the opinion that E85 is awesome. I saw around 18% more fuel consumption during normal in town driving, less at highway speeds.
The 30% figure is basing the fuel use on btus. There is much more going on when it comes to internal combustion than btu. It makes the whole discussion null and void if only comparing British Thermal Units.
More cylinder compression means more energy from ethanol. Unfortunately a motor made with the proper compression for ethanol (14.5:1) won't survive on pump gas so it's rarely done. Most of our comparisons come from people running motors built to survive gasoline. Ethanol will run in these motors but it won't be at it's best.
This is why ethanol shines with forced induction. Increased cylinder pressure means more energy from ethanol. It's a very safe fuel. Detonation isn't going to happen.
Like everyone else said the rods will probably be the weak link.