3. Buy either a tuner or the Pedal Commander for my truck. This one is the most difficult to decide on. Not having any experience with either, I'm not sure what I'm missing by not having it and I'm not sure which would be the better upgrade for my situation. My truck is a pavement princess and all we do with it is go to the drive-in and pull the pontoon boat to the lake. I drive it when I'm off work but that usually consists of short trips one or two days a week.
just my .02 cents....
i would do a pedal commander and save the rest. the most ideal option is to run pedal commander AND tuner, but that is advice best served for the 5.7/6.4 guys.
being that you have a 3.6 truck, i don't know that the canned tunes in a diablo (or any tuner choice, for that matter) will be enough to really make a difference. and a canned tune is really just one and done. you can swap between fuel efficiency (why would you with a 3.6 though?) tow, and performance. but it's arduous and probably won't net outstanding gains.
the pedal commander, even though it's a very simple trick, is an awesome one-trick pony. adjusting throttle sensitivty makes a huge difference. you'll also be able to get really granular and specific with dialing in the throttle response, and it will make your truck feel 5x as snappy off the line and while passing because it removes from 25%-90% of the lag. the smile factor will be much higher, and you will appreciate the versatility more than i assume you would with a tuner and canned tunes.
if you could run the pulsar on your truck, i'd say go that route. the pulsar is a little bit of column a and column b. canned tunes and throttle sensitivity, plus tire and gear changes.