Ahhhh you have a convertible on the rack I see.
Even WITH the MB computer, breakout box, and Star software........it's EXTREMELY hard to change anything in the ECU.
You are correct, but, the factory FUEL system can handle aprrox 8lbs of boost. Put bigger injectors in there, then even more. Do you want to run 25lbs of boost, then run a 12 injector set up. The fact is that most people won't boost their x-fire over 10 psi(turbo), so the only thing you really need to worry about is the internals, and how much they will hold. If you are willing to start digging into the engine, then chances are you can afford the fuel upgrades needed.
BTW, One of my SRT8 friends who deals dirrectly with deitweiller (sp?) has informed me that they have some DC engineers moonlighting over there, and they may have, or are close, to cracking the code on the SRT8 controllers, and theirs is just like ours.