OK, if that works for you Good Luck.. It would be my guess that you will be working the truck harder than you want to get the performance that you desire and in the long run using more gas to accomplish what you will want it to do. I would think that you could change your order before it gets too late. I have seen some with gearing to high to allow for a good driving ability and they have to make up for it otherwise. Then you see the truck on a used car lot.
I have no issue with the 3.42 gears and with the taller tires on my truck, I am definitely not to low in gearing. I run a decent RPM on the highway and get a good 19 to 20 MPG on my daily driving (That is mixed highway and city) Let us know how you do when you get it. Maybe I am too power hungry and performance oriented to see the good side.
There are programmers out there, but I had a friend do a EFI Live tune on mine. That is a little more adjustable than a small box program can do. I would also look at the power enhancers that are available on the market. Cold Air kit, free flowing exhaust.
The latest Super Chevy magazine had an article on getting more HP out of a 5.3 Chevy engine. They gained over 100 HP total, in stages to show what works. The cold air kit and the headers were a great combination and added approximately 40 horses. They did one at a time and showed on a dyno the changes. These engines respond well to a little massaging.
http://www.superchevy.com/technical/...ild/index.html