Myself, I would go with a smarty. A smarty jr will keep EGTs in check and will be easy on the tranny, the smarty sr. is good if you plan on throwing more go fast stuff at your truck as it has many settings to grow with addition of other aftermarket stuff.
Be cautious of programmers that add fuel(pressure) they are hard on injectors, a programmer that uses timing with "some" fuel pressure programming is best.
I use the smarty jr. According to manufacturer can tow at any setting (40,70,100hp) up to factory tow rating with no temp issues. This is what sold me on it. I tow a 13,500+ fifth wheel at the 100hp setting with no problems at all.
2005 Dually SRT-6 Turbodiesel
CTD 6-spd 4:10 gear, *** shift ****, Aero 4040XL
Quad Scout monitor, AEM Brute force air intake, Smarty jr.