Every time I hear of one of these 'tuners', I have to wonder this: As stiff as the competition is between the big three manufacturers, and despite the multiple millions they spend on developing one of these trucks. Why didn't they tune the truck to save the most fuel in the first place? They fight over fuel mileage in their adverts. They have hundreds of engineers. It seems like they would have found this miracle tuning themselves.
Have you heard what Ford did to get an extra 40 or 50 HP out their 6.7L engine? They changed the shape of one of the pipes to the turbine--flattened and widened. Giving it a cobra head shape. Now if they are working at that level of detail how could they miss something that a couple of guys discovered in their garage?