The last video is almost what mine sounded like when the PTO gears on the SC were going. I was able to get another 15,000 miles out of it before it really got loud and left me stranded on the side of the road. Car had 114,000 on it at the time.
Rebuilt units can be found at Way Motorworks.
https://www.waymotorworks.com/r53-r52-standard-rebuilt-supercharger.html