There were quite a bit of problem with the 3 珠差設計.
Mugen 'forgot' to design a spring washer in the front/rear diff, adjustment was almost impossible to get right, either too tight or too loose.... and the 設計 basically disallowed any addition of the missing piece...
The middle 珠差 was better by a little bit, also forgot the the spring washer but it can be easily add back to make it very nice and smooth with some good diff lub, e.g. AE lub.