Joe Romas wrote:
That 6 position number on each injector is not a serial number
It's the various parameters of each injector. If you took it to a dealer they should have programed them into your ECM as part of the job
Now if it's necessary or not Bosch seems to think so or they would not have gone to the trouble

It is true that all of the injectors need to be balanced to run smooth and have good performance. Back in the old days when the opening pressure was adjusted with a screw driver or shims, I make all the injectors crack at the same pressure and had better running engines than the techs who would just put some at the top, some in the middle, and some at the bottom of the range. On the older Mack truck engines, the injection pump plungers rack adjustments were set to their respective injector and the tech had to install them the way the injection pump shop set it up or the engine would rum like crap.
With emissions requirements and performance desires, what I suspect Bosch does is test injectors after they are put together and sort them into batches that perform the same. Then they etch numbers onto them and have a tweak in the tune to compensate for the variations. With the tuning tweak, they all run the same and comply with legislation.
At first there was no rebuilding option for Common Rail Injectors, but now there are many Diesel Injection shops who can do it because diesel owners demand it. I found a place not to far from my home and another member found out they will also do other diesel related repairs he needed.
When it comes to Dealers, there are a few good ones out there, when I was a Factory Rep many years ago it was about 25% of the Dealers had good Service & Parts, the rest were mediocre to say the least.
With the Diesel Injection pump shops, they have the EPA and various state agencies giving them the anal exam on a regular basis. Plus the quality requirements of ADS keeps them in line. If the don't do work beyond injection pumps, injectors, and Turbos handed to them, they all know what Diesel shops are good and which are not.