I have had very good results with E85.
My S13 with a ca18det completly stock engine exept for an exhaust cam on the intake side and a GT2860R made 352hp at the hubs and almost 450Nm at the hubs on a peak boost of 1,55 and 1,3 bar on peak power.
A 100% identikal s13 exept for normal 98 fuel, and smaller injectors and a pressure of 1,33 al the way made 286Hp and just over 300Nm at the same day in the same dyno.
A S13 like this normaly makes 280-300hub horse power depending on condition of engine and setup so I got a good 15-20% increase in power just with E85, you will need a lot bigger injectors and fuel system but I cant se any downsides with E85 exept there is only 1 gas station in my town here in Norway that sells it..
So 286Hp and just over 300Nm on 98 and 352HP and just under 450Nm on E85 with basikcy same boost when maks power