I have a 2011 Laramie with the hemi. For over a year, I've been experimenting with the octanes trying to find the best for mpg and performance. Alas, I give up! It seems to always vary. Sometimes, 87 is best and sometimes 87 sucks. The same goes with the other octanes. I've come to the conclusion that it's the particular gas I fill up with and not the octane. In other words, today's fuel is horrible, and you just have to hope you filled with a good batch, no matter what the octane!!!