Looking at the parts book I see that there is a single part number for fuel injectors for all P38 models, regardless of GEMS or Bosch. ERR6600. However I note on other sources these broken down into early (ERR722 for GEMS) and late (ERR6600 for Bosch).
My question is, are they in fact interchangeable? Do I take the parts book at face value, or should I find ERR722 for my GEMS and not grab the ERR6600 which is more readily available.