I just picked up the new Bully dog - Triple dog GT. For my 03 Vortex 6.0L it gives me a bunch of options. Four programming modes, performance, tow, regular, and stock. I can change gear ratios, tire size for speedo correction, and shift firmness. I have only used it on one trip (200 miles) and gain about 1 mpg on regular mode. I also did some testing in performance mode which really wakes the 6.0L up. The driving coach feature is really nice if your about saving fuel. I was not a fan of the display at first because it is rather small but now I am really liking it because it does not blind you at night and is still very readable. Bully dog has a youtube video that gives you a better overview.
