First of all, it sounds like you have some really good ideas and the truck should turn out pretty sweet when you get it all together.
The injectors will most likely be in the 60 lbs. range, 48 lbs. worked for me but i am only running 5psi at the moment. Allen should know about the pumps ability level, not positive about that and dont want to provide bad info.
The speed limiter can definatly be removed, in fact, most of the time I think Allen bumps it to like 140ish or removes it all together automatically with the tune.
I think Allen would let you keep your stock core, but I assume there is a core charge. But for your protection Allen keeps a detailed record of the the tunes, including the stock one, and would probably send it to you if you needed it.
Typically Allen recomends at least a shift kit and a servo. But having the cooler will definatly help. In any case when you run that much hp through a stock drivetrain you are bound to break something.
From what i have read and talked to Allen about a "turbo" cam will move your power band either up or down in your RPM range rather than give a lot more hp. Someone with a cam and springs are probably better suited to comment on that though.
I am actually shopping for a larger throttle body myself, so if you find one let me know too! Unfortunatly though from what i have heard there isn't a lot to choose from so you may end up having some guys that would buy it if you made it.
I am not the most educated in forced induction, but i do have a little experience. I just wanted to comment since you had some legitimate questions, and I didn't want ducky to be the only one. hehe Allen would be the best person to chat with and get a good idea of would you are getting into. The Trick Turbo system sofar is awesome, but there isn't really anything that can go wrong with it. good luck