Just seeing what people use with e85. I've heard that you should go down if using e85. I am running ngk 6 but yesterday I actually went colder to 7s and will see how it goes. Will probably go to back since the 6 wasn't causing issues as far as I know. I'm running a hotside mp62 with only 13psi top. It's a street car.

 

I don't run e85, but I can highly recommend ngk ruthenium plugs for the best ignitability. I run a #7 on pump gas @18psi. So with your lower boost and cooler CC with ethanol I think a #6 makes sense.