Terry, Congrats on your purchase, and welcome to the Forum!
I can't comment on the ACSD. Most 2LT/2LTII/2LTE engine variants owners here do some tweaking on Boost.
Your engine variant doesn't have any smog stuff to remove, but you may want to check the condition of
your glow plugs if you are having trouble starting. Mine were in really bad shape when I purchased mine.
Just so you know, the 3L and the 5L versions aren't an indication of displacement, just nomenclature. (they have somewhat larger displacement, but are not 3 & 5 liters of displacement respectively as it may first appear with that "L" after the number).
Also, the 3L and the 5L don't come with stock turbos like the 2LT variants. So I wouldn't expect too much of a power gain by swapping in another L Engine variant (probably not worth the trouble or cost with this family of engine). A lot of members are happy with installing an Intercooler. Plenty of threads here on that topic. But do your own research.
Again, Welcome to the Forum.
Plenty of smart people here to help you sort things out.
Don