hks

I am changing four injectors in my c300 along with coil packs. My scan tool allows me to code them but it shows the old code stored in the ecu for each injector. How does this coding stuff work? Should the old code be applied to the new injectors or should a new code be coded back to each injectors? I read some stuff about scanning the new injectors bar code for new codes and I would like someone to tell me which way it goes.


Thanks