It would help, yes assuming there is a reasonable restriction in the loop. While the heat from the second pump added to the fluid would be minimal there would indeed be a performance gain. The residence time of the fluid in the HE and IC is the same overall as a slower rate due to the fluid returning quicker to the devices in the loop. The faster the fluid flows the more temp delta it sees and the better heat transfer as long as minimal heat is added via the second pump.