hello
Tuikku is right about as saying at N57 single turbo with its own High pressure fuel pump could get 380-400hp (depending pump code,70 or 75).
injectors can handdle much more.
turbo will be limitting horsepower increasings,you will get OEM turbo 330-350hp (Finnish one,longer legs than USA).
referens:
BMW F11 2012 535d (313hp version)
M550d pump.
Wagner intercooler.
DPF/CAT delete.
programming. 2.4bar boost.
447hp and 870nm (Finnish one).
Greetings
Pasi
