Had little play with them attached to a 240 rad.
The problem is I only have SP120 High Pressure series to compare with.
You need to connect them to a fan controller to spin at the same rpm for a proper test.
Saying that I did connect both to a fan splitter connected to a 9v battery and they do push a lot of air for sure.
The Pro's seemed to be spinning at a higher rpm for the given voltage and produce a higher air flow.
The one thing ill say is that the new pro's have a solid and more rigid frame and are heavier. There is hardly any vibration felt in the frame when holding them compared to the SP fans spinning at a lower speed.