What are the diapragm thickness on these two? I hear the SM is 6 micron, the Beta is 3 micron (therefore more detailed), but you oddly, you don;t have that information posted. What are the other differences between the two that warrant a higher price on the Beta?
The information you are requesting is a trade secret. Sorry, we will not reveal that information.
The answer to your second question is at: Beta models vs. SM models
The relationship between a Beta 58 and SM58 is the same for the Beta 57 and SM57.