This videos shows you have to change and code your own injectors on a BMW N54 motor. Software used to code the new injectors is INPA.

Link to the thread that shows you have to setup INPA:

http://www.e90post.com/forums/showthread.php?t=918608

Link to where you can buy the cable needed:

http://www.amazon.com/INPA-DCAN-Diagnostic-Cable-Interface/dp/B008MY1F8W/ref=sr_1_1?ie=UTF8&qid=1448748480&sr=8-1&keywords=inpa+cable