I run two HEMI powered vehicles and both have the DiabloSport Predator loaded on them. With respects to the truck, I just went with the 91 CAI Octane tune with a few tweaks specific to the truck. Combined with a cold air intake (AFE) and an aftermarket exhaust (Magnaflow) my highway mileage improved 4+ mpg. Around town it improved 3+. I suppose it would be even better if (1) I cruised at 65 vs. 75, and, (2) if I kept my foot out of it around town.
As far as HP and torque improvement, take a look at my Ram Mods link below, go to page 2 and take a look at the dyno sheets for some results of before and after the Predator install.
I also have one on my 300 SRT8 with a custom tune stacked on top of it. It became a sideways beast....just the way I like it....
There is no Predator or Trinity available for the 2011 HEMI truck but they are working on it.
What I like the best about the DS products is their flexibility as you modify your vehicle and the tuning options. It will hold multiple tunes (in addition to your stock tune) so you can select a tune for your specific driving needs at the time.
So, if I've gone on too long, well that's how it is. I appreciate tools that work and the DiabloSport programmers work really well.