I was hoping that one of the techs from the forum would confirm the info. However, my friend that told me about it has been a certified Mercedes tech for 8 years.
I've changed injectors in a few "CIS" cars and never had a problem. Once I found out about it I always do it. With the proper pump it can be done in 5 minutes. I'm not sure what they would charge for it. I just take it down to my friend at the dealership and he does it for me.
If done and you still have a problem, at least you can eliminate the injectors. I just don't want anybody repeating my mistake. I eliminated the injectors because they were brand new. The car drove me crazy until I talked to my friend about it.