There is no "break in" necessary for injectors.. But all older style N54/N63 injectors are shit. As long as you got them replaced with the new style index 11 or higher injectors and calibrated the new values to the DME, you should be set for a while.
'11 135i DCT - Stock - Traded in.
'97 M3/4/5 - Boosted.
'98 Z3 2.8 Roadster - AKG poly everything, GC coilovers. 220k and climbing.
'13 Smart Fortwo - DD/beater.