You need to get one that says it will fit the IE300/IE600/IE900 as it's recessed. None of my regular MMCX would fit. Apparently you can possibly mod a regular MMCX if it has plastic red and white/clear bits at the end by cutting them off, I haven't tried this. Regular MMCX for sure won't fit though.

Stock is a terrible cable. It was riding up on my ears too. I replaced it with this one, under $10, AliExpress link is on the Imgur page.

Key is the MMCX connector needs just about 1mm of golden bit, so it will fit. I have seen some other MMCX cables that look like they would fit, but there are enough advertised to fit that I just got one that says specifically for the IE600.