aside from the one bad batch every now and then i do see a difference in milage in my Nitro. I get the best milage using Mutual. I get the worst using Mobil. Same driving no matter which i use as there are 8 or 9 different brands right around my house. Seems to run fine on any of them but i do get more miles from a tank burning Mutual. I use the regular 87 octane.