Popular kit, read carefully. Mostly this is about the specification that decides whether something fits, which is rarely the one the listing leads with and almost never the one the reviews dwell on.
Eleven parts, every pairing checked by the rules, and the two places where the obvious choice is not the right one.
Every conversion video on YouTube points at the same Bafang mid-drive. Three quarters of them are filmed in a country where it is legal.
The reviews are right that it is the best cheap printer in years. They are quieter about the one number that decides what you can put in it.
Battery listings tell you the two figures that decide range and none of the figure that decides whether it can actually drive your motor.