because some of the scenarios involve racing so E85 will be useful to squeeze some HP in race engines
Not likely, as the game isn’t really built around the scenarios. Possibly eventually though as some places do have it as a road car fuel (you can get it in QLD here, and at some places in VIC and NSW)
… And here in France we have at least 600 E85 pumps, it would be great if I could see how much horsepower I can have from my '96 BMW 728i thanks to the game 
(No, I won’t do it myself IRL 
)
Anyway, I can’t wait for turbo and V12/V16 update, keep on !
A 1 liter v-2 (500cc/cyl) Honda motorcykel engine can be modified to make over 300 hp on E85.
1.8 bar boost, and 12.5:1 comp. ratio.
So your BMW engine should be able to reach 900+ on E85. 