Here is the basic breakdown how each truck pack has been done:
We start with an ideas and brainstorm for what would be cool to add or do. new trucks, parts, skins, physics, etc.
We start to work on it, this year was even more tough as we lost people that were a big help the year before, Crazy, Casey, RKM (regardless of everyone's opinion he did alot of work on the before packs), etc
So in short there were things that we added and things we didnt (due to time, testing, etc)
This does not mean these things wont be added to the next pack revision (this is why this is the 4 iteration and not a finalized type dealio)
we dont make money for doing this, we have lives outside of the computer screen and we only do this because just like everyone on the site, we love this sport/hobby/life style.