I have a 2015 LT with 51,00 miles on it. I get 16-17 mpg in city and 20-21 mpg on highway. I ordered it like my other Tahoes with the trailer tow package. That gives it a 3.42 axle ratio. This is my 3rd ordered Tahoe since 1996 and all 3 of them got better economy than equivalent year standard geared Tahoes owned by my friends. Probably 2/3 of my miles are highway and I typically set the cruise control at 4-5 miles over the posted speed, so it's not that I drive 55 to get that economy.
I lowered the back about 1" and used softer springs to smooth out the stiffer ride of the trailer package springs and added HID headlights.
Not sure if some of the people are aware that slight low speed vibration (some call it buffeting also) is caused by only 4 cylinders powering the vehicle when the DOD is active for better fuel economy. The vibration is almost insignificant and not even noticed by most drivers.
Love the vehicle.
