I don't run an amd based system so I have no idea about the cool n quiet thing...however I would suggest you run 2 identical fans for the rad...in my case I use 2x noctua fans that are designed for this application and run quiet..They have proven to be very effective. this model
Noctua NF-P12 120mm Fan [NF-P12-1300] - $26.00 : PC Case Gear
you can mod this watercooler also btw...
(Guide) H50 Replace Tubes and Res Mod. - Overclock.net - Overclocking.net
guide for doing so if you wish..I used a XSPC bay res rather than the Swiftec one used in the guide.