No power 1/4 less the fuel mileage JOKE !!!!
The worse mileage is true, but the no power is wrong.
It can generate a lot of power, but is best utilized in higher compression applications than a lot of street cars run. GM actually published different performance figures for their new direct injection motors for E-10 and E-85. There was a pretty significant performance difference, but yes the mpg's suck compared to regular.
GM rates the current 5.3 at
E-10 355 HP and 380 TQ
E-85 383 HP and 416 TQ
That's a gain of 28 HP and 36 TQ, it will get worse mpg's on E-85 though. Performance wise it will turn your GM 5.3 into a Toyota 5.7