Kiseki and Lyra Cartridge Dealers in Japan and Taiwan

Ooops!  I just thought of a reason why 2J might change the serial numbers:  To protect his source of ZYX cartridges.  This was already described by Viridian.

A faked serial # would be to protect his sources of the cartridges that he’s redistributing as gray-market goods. Presumably his suppliers would be breaking their distribution and/or dealer agreements with Zyx. Obviously you’re not getting warranty support either way. And possibly you can’t get re-tip/exchange/rebuild services on these units, either - which is the real loss. How often does the actual warranty on a cartridge actually come into play? They more likely meet accidental end or a natural death.

I agree that 2juki is most likely providing otherwise genuine products on the gray market, rather than counterfeits. Could still be worth it if the discount is steep enough. The markup from distributor to dealer to consumer is ridiculous considering they’re often just dropping an 8 oz package in the post. These very markups, the low-volume nature at higher price points, and the ease of shipping small cartridges, is the reason these gray market loopholes keep cropping up.

In my opinion it is better to buy a demo unit from official distributor or used sample from another audiophile, those carts are under warranty and can be upgraded by the manufacturer easily.

I think it's better to do both, if you want to do both.  I've bought new units, second hand units, vintage units, demo units and review units and have been equally happy with either.

The markup from distributor to dealer to consumer is ridiculous considering they’re often just dropping an 8 oz package in the post.

Indeed.  Hence almost all of my new cartridges have come from 2juki over the last seven or eight years.

By now I have owned so many cartridges that my memory is failing me.  (Plus, my memory is failing me anyway.) If I recall correctly, the Supex first hit the US market in the mid-1970s.  At that time, I think I was listening to a Grado TLZ.  As you intimated, the Supex was the first MC cartridge to come to the US, or very close to it. One needed a "pre-preamp" in order to step up the gain, because SUTs were not yet readily available.  I think that was the Mark Levinson JC-1. ("JC" being John Curl.)  My neighbor bought both a Supex and a JC-1, and I remember not being tempted to give up my Grado in order to make the leap.  The Supex seemed to homogenize complex musical passages.  But there are so many other possible explanations for what I heard that I would never insist that my observation was accurate.  And maybe the first version was just a Supex SD900, without the "Super E+".