i have td4, and it isnt basshead iem- sounds musical like soundmagic e10, only better clarity.
cable terrible, due to thick material, it even doesnt have chin slider, which would dramaticaly improve usability.
i use it with soundmagic cable guide, without them, td4 is useless.
and i havent noticed driver flex, and i tried it with soundmagic foam tips- terrible result, thin sound.