There is pressure drop across any intercooler. An air to air will have more then the much smaller water to air will. That is simple physics.
There is also pressure drop/flow degradation due to piping length, diameter, and the number of bends (past a certain point). The turbo must spin faster to produce the same amount of boost when filling up a larger volume.
Yes the standard Duratec is slightly more boost friend (9.7 vs 10), but .3 CR in the grand scheme of things is not a tremendous amount considering both are well past ideal compression levels for adding boost.
What other alternative for end user PCM tuning do you have at your disposal & how significantly cheaper than the E-manage is it?
If you really have such a unit at your disposal I would likely eat crow to get one. Nothing of that nature is available here in the states.(no "nationality" slur intended
)
BTW - I neither have nor am affiliated with the Street Flight group or turbo. I just thought your slam of them was very unprovoked and miss-leading so I countered. Feel free to ignore me or not. Just be aware that by not answering my relevant questions you may end up looking worse in the long run.
Good luck finding room for 2 turbo's under the hood and even more luck with the intercooler placement and pipe routing. Not to mention all the heat they will produce and inflict on the underhood components.
BTW - Does this kit come with a new front bumper cover and what about the A/C condensor & radatior and airflow to them?
Such a simple approach! I like it. 
