SO was that dyno on pump gas? If so that is very impressive, right choice going with the E85 fuel.
I second this ^^^^^^^ Turbo technology has come a long way, especially in the last 5 yrs take advantage of that and don't be afraid to go bigger there are tons of 4 cylinders running 72mm turbos. with your transmission you should have no problem keeping a turbo that size in it's sweet spot(In terms of engine rpm). if you plan on spraying it off the line anyway that should help spool it up on the bottom end plus an anti-lag system via your ecu.