This may not be considered a performance "mod" but I am obviously a Newb here, I have an N55 E92, just got a JB4 S2 with iso. I have heard of people running a mix of E85 and 93 fuel to get more power. How safe is this on a fully stock engine with just the JB4 and how do you go about getting E85 and determining how much to mix?
2011 BMW 335i E92 Vermillion Red, 6MT [SOLD]
2008 BMW M3 E92 Alpine White, 6MT