Quieter HDD cooling in 24 bay case

[nry]

I currently have an Xcase RM 424S (similar to the Norco product), which is a 4U 24 bay server case, with 17 HDDs. My motherboard is an Supermicro X9SCM which from what I gather only offers speed control of PWM fans.

The case... http://www.xcase.co.uk/rackmount-ca...it-included-pvm-120mm-fans-249-00-x-case.html

Currently I have 3x 120mm fans which are 3pin and have a spec of roughly 50CFM. Needless to say it sounds like the case is going to take off! as they run at full speed all the time.

I would like to change these fans to PWM versions so the motherboard can control the speed as required. Just wondering if anyone has any suggestions of fans to use. Currently I am looking at the following:

Corsair SP120 PWM High performance edition - 62CFM - 35dBA - http://www.corsair.com/en/air-serie...ce-edition-high-static-pressure-fan-twin-pack
Noctua NF-F12 - 55CFM- 22dBA- http://www.noctua.at/main.php?show=productview&products_id=42&lng=en
Arctic F12 Pro PWM - 57CFM

Basically unsure on which route to take, the Noctua's come highly recommended but also come with a nice price tag!
Any suggestions? Someone else must have changed the fans in one of these cases