I would recommend an air cooler like the NH-D14 or NH-U14S since they are the best air coolers you can buy. They will be able to overclock your FX8320 up to 4.7Ghz without a hassle and they will be super quiet. With an air cooler you don't have to worry about pump failure or leakage. Here are some in depth reviews of the nh-d14 and nh-u14s handling a 3770K at 4.6Ghz.
http://www.relaxedtech.com/reviews/noctua/nh-u14s/1
http://www.relaxedtech.com/reviews/noctua/nh-l9i-nh-d14/1
http://www.relaxedtech.com/reviews/noctua/nh-l12-nh-u9b-se2/1