I've used Witch Girl 12 with my 3-year-old Toxic Cables Virus in the last 4 weeks and the result is very positive.
Though the soundstage width has been a bit narrower and less sparkly treble than the stock cable but the mid has been brought more forward, larger, and more robust. The upper bass gets faster and punchier.
Especially, after listening through the WG12+Virus for extended periods of time, I don't get any ear fatigue.
Last week I went to a shop in Bangkok to try some aftermarket cables pairing with the WG12. I tried Labkable Pandora, Effect Audio Lionheart (with PSquared plug), and Dita Truth Cable with Awesome Plug.
I love heavy metal so during the listening session I used just one song for the comparison, Trivium - Torn Between Scylla and Charybdis. The DAP I used was AK240SS (SE only). I swapped the cables just with the demo unit (with Spinfit tips), my WG12 stuck with the Virus and the black tips, so the results from the two WG12 may not be consistent.
The Pandora was the best (for me), it has amazing dynamics with richer mid and upper bass. The drums hit harder and the lead vocalist seemed to be more muscle. The treble was crisp and clean with a lot more energy than the Virus.
With the Lionheart, WG12's soundstage got narrower both the width and the depth and less transparency. The treble was on the same level as the Virus but very powerful. The overall sound was neutral and natural with good details, impressive.
I think WG12 with the Truth was not a good pairing. This combination sounded dull with narrow soundstage width while maintaining good depth. But I really love the Awesome Plug, it's really awesome.
If money was no object for me, I'd be a no-brainer to go for the Pandora. Ideally, the Pandora with the Awesome Plug but that'd be impossible.
The Lionheart was a very good cable and very light. For the Truth, IMHO I think it should be paired with some other bright earphones e.g., Noble Kaiser Encore and CA Andromeda.
I'm just a noob so these impressions are just my two cents.
I'd like to thank you Munkonggadget for letting me using these cables for hours.