I added the Range DFM disabler to my 2020 Sierra 5.3, 10 speed, 4x4. I had previously added a GM Performance CAI and Borla S-type exhaust. The exhaust just sounded strange when the dfm kicked in, so I got the disabler. The truck sounds alot better now, but my mpg dropped from 22 to 19 with the disabler.