i had mine on E85, all i changed was the tune.
my 600cc injectors hit 100% on 22psi making 300kw
tuned it fairly lean on cruise and still wasnt the best on fuel. but admittedly i dont cruise it all that much
BUT THEN
on my way back from a photoshoot in sydney i was down to the Empty line and had 40kms to get home, wasnt going to risk it so i put in 6litres of E10
that was the turning point for me, i put it back to 98 last week,
things i liked about eflex is there is no soot all over your car and the smell, my setup is maxed out so i found no gains at all running E85 except for on the track, E85 has a higher knock limit so was a bit of reassurance