I think I remember a video of yours where the crank was obviously wobbling. I was following those 'wirring' threads too because mine does it, but only if the temp is below about 40 and only for a few minutes until it warms up. And not really loud. I told a mechanic I know who's worked on these full time all his life and he said it can come from a crank bearing with a pit, But he said it wasn't that in my case because it would do it all the time. It's been two or three years and it's not changing, so I'm not very concerned.
The same guy, once I told him had to replace the diode inside one of the relays and I started to tell him what the symptoms had been, and he told me what they had been before I could! That amazed me. Especially now, since I can't even remember for sure what the symptoms were myself.