I never found the issue with my coolerworx but the buzzing/rattling stopped when I grabbed the cable too. Makes me think the inner cable is rattling against the outer housing. Since I've had it installed in my new Z, it barely happens. Maybe the cable is routed differently. I did message Nik Soho and sent a link to a thread here that multiple people are having the issue. After months of not getting a reply, I sent another message and he replied said he's never heard of the issue but needed a video to send to coolerworx. I told him there was a video in the link I sent and I never heard back from him after that.
