if your fitting a garret turbo then the stock injectors wont fuel well enough without increasing the fuel pressure at the very least.
standard engine is capable of around 1-1.2 bar of boost and producing between 200-250bhp.
you want to go any further than that and you need forged internals.
as for the management side of things. stock ecu is ok, but you will have a fuel cut limit at around 0.9 bar and obviously its designed for use with the standard turbo setup.
a basic rule of thumb for the injectors is that if your staying ct9/hybrid ct9, stock injectors are fine. anything bigger and ou should look to upgrade.