2 piece driveshafts

I have been told by the shops that they do not even try to do anything with those shafts, but just build new solid tube shafts to replace the dampened ones.
Quotes were about 200 for a new built.

Interesting note,
Boat props are built kinda like that, and you should see what happens when the rubber gives in one.
It'll freak ya out from the noise and vibration.
You'll think your gearbox is trashed.