Quiet 140mm case fans?

[yiplong]

Currently have two Cooler Master R4 120mm exhaust fans, they are okay, but not quite as quiet as I would like them, and they don't move as much air as I want, so I think I may replace them with a pair of 140mm fans.
The R4s are rated at 20db, but I think they are more like 28-30 db. The 140mm fans definitely cannot be any louder than these, ideally I would like the new fans to be much quieter. Let me know what you suggest.
Currently I am considering the Xigmatek XLF series like this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16835233031&cm_re=xigmatek_140mm-_-35-233-031-_-Product
or Thermalright X-Silent:
http://www.amazon.com/Thermalright-X-Silent-140mm-Silent-Fan/dp/B002U4Z6NA/ref=sr_1_1?ie=UTF8&s=electronics&qid=1265428450&sr=8-1

These 140mm fans are rated at like 16db, but I don't really trust the manufacturer's data.

 

[JohnnyLucky]

I checked a few references. The Yate Loon and Scythe 140mm case fans are about as good as it gets.

 

[abhi_jollyguy]

Currently have two Cooler Master R4 120mm exhaust fans, they are okay, but not quite as quiet as I would like them, and they don't move as much air as I want, so I think I may replace them with a pair of 140mm fans.
The R4s are rated at 20db, but I think they are more like 28-30 db. The 140mm fans definitely cannot be any louder than these, ideally I would like the new fans to be much quieter. Let me know what you suggest.
Currently I am considering the Xigmatek XLF series like this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16835233031&cm_re=xigmatek_140mm-_-35-233-031-_-Product
or Thermalright X-Silent:
http://www.amazon.com/Thermalright-X-Silent-140mm-Silent-Fan/dp/B002U4Z6NA/ref=sr_1_1?ie=UTF8&s=electronics&qid=1265428450&sr=8-1

These 140mm fans are rated at like 16db, but I don't really trust the manufacturer's data.

If u want the best Fans so buy anyone of these

1. Scythe Kaze Maru (SY1425SL12H)
2. Thermaltake TurboFan 14 (A2491)