I would suspect 2X6 there would be little to no changes. According to the specs, the crossover point is the same and I believe it still uses the mechanical roll-off approach. If there have been such changes to a full crossover they have not been stated. According to Axioms stance on crossover components you shouldn't expect any enhancements to the build quality in the V3 crossovers either.
There was a picture of the M80 v3 crossover over at the blu-ray axiom speakers thread but I can't seem to find it anymore. IIRC the layout of the components looked different from previous versions but can't tell much else from just looking at a picture.
