I would agree with Mer. To expand on that, if the 57,000 ksi and 37,000 ksi rod have the exact same action, the 37,0000 rod will PROBABLY be heavier and probably have a slow recovery speed.

I say probably because modulus only refers to the carbon fibers, and doesn't account for the resins and scrim. So it only relates to one ingredient, not the overal product.

That said, I wouldn't focus so much on rod modulus. Compare action, power, and blank weight-- that will give you a better comparison. And if you want to get technical, do a search on the common cents system, that is truly the best way to compare blanks, short of casting each one.