I spent another hour comparing cables and the findings are in line with what I wrote above.
All comparisons done with Mojo as source.
Original FD02 cable from JVC:
Clearly the worst of the 3. In comparsion to them, it sounds dull, lifeless and uncontrolled. Busy passages become shouty. Bass is kind of bloated and uncontrolled.
Soundstage is narrower and less deep.
Nobunaga Yuzen:
Much more open and airy, clearer, vocals floating, soundstage opens and gets depth. Bass is better controlled, but still the overall impression is "full", like a full mouth.
Smooth and slightly warm sounding, slightly round compared to silver cable. Can get a little shouty in busy passages.
Compared to sliver cable it sometimes feels a little veiled.
DIY pure silver cable:
Even more open and clear than the Nobunaga. Snappy, faster impulse response, bass tighter, drier, but also a tad leaner (perceived). It sounds brighter, cleaner and clearer, can almost seem a little sharp.
It is clean, clear and sharp, stays clean where the Nobunaga gets shouty.
MEASUREMENTS:
I'll spare you the graphs, all 3 cables measured identically, but the perceived balance is quite different with the JVC being the boomiest/bassiest with veiled treble, the Nobunaga being much more neutral, smooth and warm with good sparkle, and the silver cable being almost bright with slighly more sparkly treble, more forward and neutral mids and cleaner and tighter bass.
Some specific observations:
Stravinski's Firebird:
https://tidal.com/track/77607310
a really difficult piece. starting at 3:15 it's really busy, and that is where the JVC cable gets really shouty, and even the Nobunaga does not manage to keep things clean and clearly separated. The silver cable gets loud but stays clean and clear, keeping all the elements separated.
Bottomline:
the original cables really hold the FD02 IEM back and should be replaced.
The Nobunaga cable is a pleasure to use, sounds much better than the original. Pity that it turns green after just a few weeks of use, and is not as clean and clear sounding as the:
DIY silver cable, which comes out on top. Slightly bright but clean, clear and with the best separation and bass control it's a clear winner in all aspects EXCEPT comfort and microphonics...
Cable used:
https://www.aliexpress.com/item/32814035621.html?spm=a2g0s.9042311.0.0.27424c4dyqdd03
FP8101AG teflon insulated 6N OOC silver wire