Had my first 360 mile road test with the Kennedy dual program ECM. Pulling 25' trailer and a light 3K load, I averaged nearly 15mpg for the day, most of it at 70mph as I was in a hurry and not trying to conserve fuel, but 'make time'. I would estimate that it was a solid 1.5mpg better than what I would have expected given the higher than normal speeds for the day.
Power is smooth, nice shift transitions and probably a better overall tune than GM ships from the factory, based on my first day towing.
I think my Predator is now demoted to 'pulling and resetting codes' duty...the Predator shift transitions are flat and throttle response is choppy and nothing you'd expect from the factory on the higher HP settings. It acts and feels 'aftermarket' in comparison to the Kennedy tune, and belches black smoke on the top settings with high EGTs.
Haven't spent much time testing the Kennedy high HP tune, but did try a few 2/3 throttle blasts with the empty trailer up rolling Wisconsin hills on I-94. Impressive. Same thing - very linear, no flat spots, no bad behavior. Feels like factory stock but lots MORE POWER than the truck came with.
A+ rating from MRE. I'll likely be adding the same to the '01 LB7, possibly integrating it with propane controls for additional range and economy.