Hello, New to the forum and I know this thread is a little old but thought I would throw my .02 cents out there. I have a 2010 DRW 4x4 with the same trans and same tuner. Only difference is I have a H&S exhaust manifold and borg warner SX-E 63mm turbo with 5" exhaust. My truck absolutely sucks on MPG towing or not on the low settings. If I turn the tuner all the way up I gain alot of MPG. With no trailer on stock settings and even 60hp tune I will get 10-11mpg at best on the highway at the speed limit with cruise. Now if I turn mine all the way up to the 200hp tune and make the same trip it will get 20-21mpg. I just made a 800 mile trip pulling my 44' cyclone toy hauler fully loaded at 70mph on the 200 hp tune and the temps all remained fine and I got 14mpg. Normally pulling i would get 8-9mpg. Truck never ran any hotter than when on a stock tune. Risky? Maybe but without high temps I dont see it as a problem. I know the trans is the weak link but I never saw any increase in temp or noticed any funny shifting. I think this may be different if it was in the hills or mountains and this trip was fairly flat. Guess I will keep it turned up and see how well it all holds together.