Having two pumps at that speed is just overcomplicating, I would take amuffins suggestion and try to sell it. Either way just get yourself a stronger pump, there's plenty of other spots to add bling in your pc anyway
Modding a closed loop cooler is ok if you want a project, but I wouldn't expect any dramatic performance increases. These coolers are developed and produced on a budget scale and are built more for the 'name/description on the box' rather than actual performance of said description.
Closed loop liquid cooling does not perform like water cooling.