2004 Mercury Grand Marquis.

On the driveshaft slip yoke there is a harmonic dampener; basically a metal ring with a layer of rubber-like material that is sandwiched around the yoke.  Rubber dried up and disintegrated and the ring is now just bouncing around.

I see a lot of slip yokes online with and without these dampeners. The only way to get a new yoke with a dampener is to buy the entire driveshaft assembly at a cost of around $350 not including shipping; and I've looked everywhere.  

QUESTIONS:

Can I drive the car with it removed, is it really necessary?

Should I take the assembly to a driveline shop to have the whole assembly rebalanced without the dampener?

Thanks everyone.