Never heard that a solid shaft performs better or leeches less power than a split shaft with a 'carrier bearing' as you call it.

Didn't the MB engineers put that in there for a reason?

Not trying to be a pain, I just don't know enough about it. A little research reveals that the reason for two piece propeller shafts, as they are properly called, is that at higher RPMs they produce resonance that can compromise the shaft. This has been the big push behind composite one piece propeller shafts.

So, is it because our propeller shafts are a smaller diameter that they require the two piece design? Is it because it's a weight savings? i.e. - two piece is less spinning mass than a single piece?

Seems this article says that two piece designs are heavier, louder and cause more vibration, but don't say why they are used except that the diameter of the shaft is smaller and can't be one piece.

Inquiring minds want to know...