The retrofitsource.com has a kit for the 2014.I had it in mine,it cost $170.00 at the time.I just traded it for a 2018 Denali and it was just about as good as my new 18.I also bought their fog light kit that I never installed brand new in box that I would sell for $125. They sell for $210.00 new.
Did you notice any difference in the ride. I just got a 2018 denali and that’s the only kit I have found for the mag ride.I was going to order Wednesday. I have already put my wheels and tires off my 2014 slt on the 2018, with a slight rub at full turn sometimes(275-60-20 cooper at/3)
The air dam might be 1/2 mile a gallon,the tires are probably 2 to 3 miles to the gallon,the level kit is 0 miles to the gallon.I did all those mods in different stages and that’s my specs.My truck hates cold weather and winter blend fuel,that’s another 2 to 3 miles to the gallon.When the temp hits about 55 degrees my mileage starts going back up.