If I read your original post correctly your Injectors have 150,000km And your CP3 has 608,000km
Last I checked the CP3 was a substantially cheaper upgrade. So if I was going to change something based on symptom that is the way I would go, especially if it is starting good.
Naturally go guarantee without a return rate flow test. I feel a new CP3 will tolerate mildly worn injectors better than new injectors will tolerate a worn pump especially at max flow/PSI demand