Might I suggest an alternative? Check out the Vantec VA4-C7040. It is quieter (45 Db instead of 62) and the same temp (51 C). Plus it's only $22 on pricewatch! It's hard to get a cooler HS/fan for any quieter.
Yep, I use it...only because the Zalman (flower looking) HS won't fit.
The vantec is a good HS, but the TMD fan does make some vibration, expecially at low rpm's (but it's still pretty quiet). It cools well, and is easy to install.
There is a Vantec AeroFlow 2 (VA4-7245) coming out sometime in Feb. that has a different fan and the clips are a little different...don't know how well it will work. Here is some pics of the AeroFlow2, if you want to take a look http://www.vantecusa.com/moreimage/image_va47245.html