I think with a injector swap it would need to be done at the shop so they tune the new injectors.
The ecu / turbo setting etc. should be tuned also, maybe even for sport ?
The ecu tries to keep the car in Stoic but it has variables and is not so smart. With my tuning box i can set it and run around pushing soot , and the ecu does not reset anything it lets it smoke happily away.
Here's a good explanation by someone who does his own injector swaps , although he is going bigger. I wanted to refresh myself on the procedure and found the info below
link:
http://www.evoxforums.com/forums/showthread.php?t=22338