I have been considering a move to E85. My car is street driven with a fresh bottom end already broke in with cast iron Bo port stage 3 porting and 2.1 cam. Rods header and 3" from the turbo back to a single 2 1/2" over the axle tail pipe. Turned intake and large NPR charge cooler. Running 18 lbs of boost with ball bearing turbo. All pimp controlled. My goal was more than I got from these mods. My question is how much more boost could I run safely with E85 vs 93 premium?