...
There are two plug to the earpiece types, type A (ZS3/ZS5/ZS6) and type B (ZST/ES3/ED12). Type B connectors need to be trimmed down slightly to fit into type A housings.
There are a few different cable types:
silver (SPC) 4-wire with white plastic connectors, angled plug
also available covered in gold colored foil with black connectors, angled plug
grey OFC SPC 4-wire with black connectors, angled plug
silver SPC tri-braid with metallic looking connectors and larger metal straight plug
Most type A connectors are straight, most type B are angled, but the tri-braid cables have short straight connectors and have only been available in type B until just recently.
For the most part the tri-braids tend towards the lowest resistance (expected given additional material). The other upgrade cables are mostly relatively similar (with some old outliers). All the upgrade cables appear to have separated ground runs.