I have run mine on my own settings 37psi front, 34psi rear. They are slightly lower than eco but not by much. I can't say for certain how much of a difference it makes because all cars, drivers and journeys are different but for me the higher pressures give me about 3mpg gain in mpg compared to comfort settings which I tried. That works out at about 5% gain for my journeys which are mostly motorway or fast A road. Just look at my fuelly figures.