SAS
You are shifting the goalposts.
I agree that a typical instructor has no need to know about modern avionics, or modern anything for that matter - partly because the JAA syllabus doesn't require it, partly because it's not what the average student needs, and very much because the number of punters who get their PPL and then buy some space-wagon with state of the art avionics and want diff training is so small that most instructors will never get one.
However the context here is diff training specifically in a DA42. That should require an instructor who is fully familiar with everything in the aircraft, and the avionics are the most complex item. I accept that my criticisms of instructors (entirely based on my experience) are going to cheese off some old hands (the ATPL hour builders probably aren't too worried) but to suggest that the instructor can get the handbook out and learn about it is frankly ripping the student off. On differences training on something like that you expect, and pay for, type specific expertise, not only on the kit but also on any relevant aspects of handling. Anybody who can work through the PPL exams will have enough intelligence to read the manuals himself. I wouldn't pay an instructor to read the handbook the day before, and know no more about the handling of it than the basic numbers.
Captain101
It has been alleged by owners that the official event log isn't representative of the real thing. Not being an owner I can't vouch for that, but perhaps there is a real and serious engine management issue there. All the publicity I've seen suggests that it is just about impossible to do any damage to the engine; the FADEC supposedly prevents that. If this is not the case, it would explain why some operators have not had any problems while others (one well known flying school, for example) have had loads. Whereas most owners operating the old iron will know something about engine management.