Ok yes lets go back to the tech and ill try harder to become more clear in what im saying.
Ok regaurdless of whether you can package it or not lets talk about the ability of the seperate systems to make power.
This is my argument for 2 turbo`s.
Advantages:
The turbo headers are easier to make
By using 2 turbo`s exhaust header manifold design is improved. Because heat loss is kept low. Therefore the boost threshold is lower with the same a/r.
By the additional improvement in exhaust header manifold design a higher a/r can be used while maintaining the boost threshold at its current level which causes less tip.
In theory This will produce more power by allowing more radical cams and port work without reversion becoming a problem.
My argument for the exducer bore is made by this math work I completed.
Showing at 750 cfm (2) 2 inch pipes will see 286 ft per second gas velocitiy.
It would take a 2 and 7/8 inch ID pipe to flow the same amount of air at a slightly lower velocity 277 ft per second.
So the exducer bore on a single turbo would have to be quite large to flow the same amount with the same amount of pressure drop as the 2 smaller turbo`s.
Disadvantages
Cost if you go with new turbo`s
Sizing 2 turbo`s appropriatly for the application could be hard.
Extra complexity at controlling wastegates and making sure water/oiling lines get to where they are suppose to go.
Extra intake pipes and intercooler piping and intercooler modifications.
Single turbo:
Advantages
Simple
Cheaper
Would be very close to 2 turbo`s in performance *debatable
You can use a huge turbo I mapped out and found a t70 would work last night if you were going after like 25 pounds of boost
So bus turbo`s from junkyards are fair play here and that means cheap.
Disadvantages
Debatibly you could drag out more power from a twin turbo system.
Header is hard to make and has more areas that could fail. Its also less efficient. There is alot more surface area and bends before the turbo to cause heatloss and turbulence.
Turbo sizing on this side of the scale could be hard to get just right depending on desired rpm range.
You would have to use a large expensive external waste gate for that much flow which is harder to control then 2 smaller wastegates. So low speed could be more of a hassle.
