Some things aren't made to have Band-Aids put on them…JMHO
Why not find out who makes your driveshaft and talk to them, or take it to a local driveshaft shop and have it re-tubed to the correct length.
Is it worth f-ing up your car (or worse) for 400.00 or whatever it would cost to do it...
Kinda hard to answer that but from the limited video I would say it's coming from the head, What kind of headers do you have? Did you use the old gasket or a new one when they were installed?
You could have more then one leak, as well so keep that in mind.
Hey I'm not saying this is 100% it...
Well, the more I listen to that the more it sounds like exhaust (and your above info hold constant with my experience) , I would look really carefully around the exhaust manifolds to see if you see any signs of an exhaust leak.
It could be something with the VCT or the solenoids.
You...