I am surprised that this problem has not been publicized more for consumers. I tried to search for this problem on the news group alt.auto.mercedes and found no entry. The dealer basically replaces the fuel sensor under warranty. As I mentioned before, The California "Lemon Law" allows 4 repairs in the 1st year. MB probably knows this and has calculated the cost of replacing vs. redesign. For now, the fuel sensor is of the same design everytime they replace it.
I will definitely write a complaint letter to MB! This problem will definitely decrease the value of my car if it continues. I would also ask readers of this message with similar problems to write MB.