The ect simply raises the shift points of the transmission, it does not change anything in the engine tuning but to raise the rpm. I feel that the shift points are too low for steep terrain and or a heavy foot but fine for highway/light foot. The ect is simply to make the transmission more versatile to meet the dual nature of the vehicle. I have had both the 5 speed and auto transmissions in my 4runner with both the different ect's for those models. The engine runs exactly the same, but the ability to raise the shift points with the 5speed makes it a completely different vehicle in power and performance on steep road terrain. Off-road is another completely different story