Audioquattr systematically measured his carts at vdh (since he is a local and has visited a few times) and his impedance varies a lot from 0.13 on GC to 0.39 for the higher output MS. With GC, he is able to get a lower impedance at a higher output, this could be due to the magnet used. For the same cart, as output lowers, the impedance drops, but for the MS to get close to the GC impedance takes quite a drop in output.
That said, both were set up on the SME 3012r on the AF3p, and we preferred the MS to the GC, slightly due to better highs - the GC seemed a tad too polite while the MS was more realistic.