I was wondering what kind of gas mileage other members are getting per gallon, and the grade everyone is using... My Escalade is 100% stock, no large rims, and I do a lot of highway driving and am getting 14.9 miles to the gallon on the middle grade of gas, plus (89 octane). The dealer told me upon purchase to use 93 octane, but I just found that wasteful since I only keep my trucks till about 60,000 miles...