My 2013 F350 has a trailer hooked up to it probably 95% of the time. Maybe its because I'm used to my former diesels and my former 5.4L, but I absolutely hate how this truck is constantly down-shifting. Yes, I'll lock out a gear or two but its amazing how much it wants to down-shift. My trailer loads are probably around 5,000 lbs.
What are some good places to start when considering tuning this truck? All I care about is getting it to tow better. If that squeaks me out a little more mpg, great. But if not, that's OK. I would think just being able to keep it from dropping down to second and then having it screaming second gear up to near 60mph would be a good place to start for saving me some fuel.
Check out monsters Ohio meet thread. The last one I attended and ran the 93 time with whatever weight the trailer was (15k lbs?) in my '11. I'm using 5 star as well, solid tunes and great customer service.