I had a 2018 2500. I now have a 2021 3500 H.O. with Aisin. The standard 6.7 has more power to the ground than the high ouput version in the lower gears during normal driving. I believe this is to limit damage to drivertrain parts. The 3500, when placed in tow/haul mode, has more power down bottom than the standard 6.7. Tow/haul keeps the converter locked up and it scoots...Much more pulling power when in tow/haul than a standard. However, the standard got 18mpg around town and 24 out on the highway(when empty). The H.O. gets 15 everywhere, everyday(empty) and it doesn't get better. The 2500 rode like the old 1/2 ton trucks....Stiff but smooth. The 3500(no air ride) rides like a spine crushing medium duty rig. The 2500 shifted like a 1/2 ton truck...smooth and predictable. The 3500 Aisin is herky jerky/clunky....kinda like the box trucks it normally occupies.