I ran across an ad in the Horsemans News touting the Workhorse Tuner. They claim 15% or greater mpg, 160 lbs increase in torque, 80 more usable hp. All this without modifying exhaust or computer, does not require gauges and is warranty friendly. Is anyone using this tuner? Are these claims true? I tow a Featherlite gooseneck w/living quarters and would like to increase hp and torque (more mpg would be great also).