Yes, I've just done all this and no joy.
I went through the spctl process and went into the system information and disabled software and still see the line6.driver.xtaudio showing under that area before re-installing the drivers. So, the process must not have worked. I reinstalled the drivers anyway, just in case and that didn't work. So, uninstalled, redo the process to no avail.
Anyone else find success?