A. "The BMW is better than the Ford because with the BMW you get 'German quality' engineering."
B. "Chocolate is more delicious than celery because it is tastier."
In the former, the premise takes for granted that German engineering is better than non-German engineering.
In the latter a synonym of the conclusion has been straightforwardly included as a premise.
I get that the latter one assumes the thing that's being argued for, but the former one seems to assume not the thing it's arguing for but rather something that itself requires evidence (i.e. that German engineering is better than non-German engineering). Only the latter fits with my preconception about begging the question, but the former is adapted from an authoritative source.
I adapted the former quote from Pinker (2014), which on p270 gives as an example of begging the question:
"When I asked the dealer why I should pay more for the German car, he said I would be getting 'German quality,' but that just begs the question."
Pinker, S. (2014). The Sense of Style: The Thinking Person's Guide to Writing in the 21st Century. Penguin.