I just got my programmer yesterday but I pick stuff up pretty quick. I cranked my truck for the first time with it at about noon today and have already knocked a few seconds off my 0-60 by tweaking the level 1 (tranny only) file.(currently 3 seconds down from stock w/stopwatch and 1 or 2 from canned lvl. 1).
To adjust for aftermarket parts and tires make a note on your order form about the performance mods and current tires because you can go back and change tire and gear sizes in the tuning menu.
Mounting is the easiest part, it comes with its own little holder ("pod") that Edge charges and extra $45 for, to mount the pod you just push it onto the flat plastic by the driver side pillar and then the programmer just pops into that. Its easy to put in and take off so no worries there.
The main thing to do is like JandJ said, read the manual. I actually downloaded a copy before I filled out my order form so I would know what to expect. Its easier to work than I expected, and it looks good. Just set the truck back to stock before going to the dealership.
I did my research and the edge came up on top and the gryphon is an improvement on that. So even if my custom tune doesn't come in, Im still happy because I'm still getting a deal.