Based upon my brief encounter with a high output (160 cfm) fan, prior to removing my FOP-32 from service, I'd wager that before you invest big bucks in a big buck HSF, try a bigger fan. Admittedly, no one with a reasonable sense of hearing would want to mount a big cage blower on their PC, but there are high output, smaller footprint fans than that, which can be made to fit the top of your existing HS. Getting the ambient temp inside the case is a close second to a big fan on the HS for reducing CPU fans. You see these horror stories about someone having a 50C CPU temp and then upon further inquiry, you find out that their case temp is 35C. Strive to keep the case temp as close to room air temp. If you live somewhere tropical, strive for an air conditioner
Hoot