I own the zs7 which has a rated impedance of 24 ohms. The zs7 stock cable according to
@hakuzen has a very high resistance compared to the kz silver only 8 core. I also have an 8 core cable from jcally which i can only assume has better conductivity than kz cables given the measurements of some other jcally cables and its higher price point.
That being said i don't think that better conductive cables will give you better sounding iems all the time. At least in the case of the zs7 i find the stock cable sounding most coherent, despite its high resistance. The kz silver cable tame bass, make mids weird and highs more pronunciated (latter being a good thing). Whereas the jcally produce better staging with a more aggressive v shape sound which is also not necessarily a good thing depending on whether or not you like a more v shape tuning than it already is on the zs7.
I seem to come back to the original cables after long listening sessions with all of the 3 different cables.
And now go along with the conclusion that, if it doesn't sound good in its stock config. Probably wont sound much better or worse with a different cable, so might as well stick to the ones the iems came with, and tuned with, unless they are physically unusable.