I really have no advice to offer, but since I'm one of the few here with one of these cars I thought that I'd chime in. I was not aware of such a vibration damper. By the end of next week my car will have 200,000 miles and have never done anything to the driveshaft.
From this description, though, it would seem that this damper would not be very important unless part of it is missing causing an imbalance or if there is something else wrong with the driveshaft causing a vibration for this device to suppress.
Please keep us informed.