MD can you explain what exactly each of these box's do that no single box can?
Well, its not always a case of this box "can or cannot" do X. It is also a case of HOW WELL they do X.
For example. The Redline (or FMS) does not add additional timing. You might have a little better bottom end torque, but you will run out of hp in the upper RPMs.
The comp does add timing, but, in my very humble opinion, does not do as good of a job as the Smarty.
The Smarty is your low-end and timing box. You will not get the same low end performance with any of the boxes as you will with the Smarty. Having gone from a CaTCHER ECM with no timing to a Smarty with timing, I can say that I much prefer the timing. I didn't notice any difference in EGT control, but the higher RPMs are stronger with timing then without. \
99.9% of the information available (and given) on any of these things is pure opinion. They all claim to do similar things. They all claim to give similar HP. In my experience, I think a Smarty stack with a non-timing fuel box is the best for driveability, and the TST with Smarty is the best for horsepower...
I would LOVE to see if there is a shutter with the TST on a monster pump. If these things are pushing the fuel as hard as everyone claims, I predict a few people on the side of the road cracking injector lines after getting out of the throttle hard... Will be interesting to see.