How would the DD DDC 3.25 pump compare to the new one? Is there a review out there comparing a 3.25 to a 3.2?

I'm looking to snag 2 pumps NOW for a EK dual pump top.

Is a 3.25 much louder then a 3.2? Could one lower the voltage to a 3.25 if need be?

Or should i just snag 2 3.2 pumps?