I have the car at the dealership, supposedly the harmonic balancer is falling apart again.

Car is a 2001 e430 with 40,500 miles.

I had the harmonic balancer replaced under warranty in November of 2003, with 23,700 miles:

112-035-13-00 Vibration AB
006-990-70-04 Screw

Questions:

1. Was the Nov 03 replacement the updated part?
2. Is this part still the most updated part? I see newer part numbers in other threads here.
3. Has anyone experienced a failure with the updated part - in other words, had to replace their harmonic balancer twice?
4. The dealer is balking at replacing this, how do I go about escalating this issue (he's not listening when I said this is a known problem with these cars).

Thanks for all your help!