Why can I use the stock ecu/mass-air meter for the turbo swap?
The main reason you can’t “safely” use the stock Mustang computer and mass-air meter is because there is nothing available to tune the stock ECU for larger injectors, a larger air meter, timing retard under boost, etc. The stock air meter and small stock n/a injectors wouldn’t support more than about 130rwhp which isn’t even worth messing with.