No and it would be difficult to test as too many variables on any given drive. Brake regen has been around for quite some time so I am sure you could look up papers that point out the efficiencies and make your own mpg conclusion. One point about regen is that it significantly helps to slow this heavy beast down! If I forget to click the regen mode at startup, my first brake zone catches me off guard and I usually have to do a panic hard brake at the end. The stock HD brakes are undersized in my opinion - probably a hold-over to fit 17 inch wheels which don't work with larger discs and calipers. That's fine for rock crawling but not hauling down this heavy rig from 75 mph off of the interstate. This will be an area I address in the future once these components wear - ss lines, new pads; possibly upgraded brake kit. Otherwise I am pleased with the ride and handling of my Sahara HA 4xe.Has anyone tested the fuel economy with and without max regen?