I have to agree - I'd buy the side panel with the fan - you need to put a wooly jumper on your SLi cards to stop icicles foming on them!
And yes, I would take the YS-Techs as for £12 each them move upto 125cfm of air. At that they are 40dB. You can hear them! At 7v they are still moving 80cfm, but now they are pretty much inaudible (at least to my 38 year old ears!).
At 12V (and still £12) the Ambers are moving 45cfm, at 7V, which is quite widely recommended, and they're only moving 30cfm which is a lot less than the YS-Tech.
In the summer, you can still overclock your machine with the YS-Techs, that's much harder with the Ambers.
I would also recommend a good manual fan controller like the Noise Isolator PWM (Pulse Width Modulation) controller. As this is a PWM fan controller, not a variable voltage one, you can run the fans VERY slowly. PWM works by constantly turning the power to the fan on and off so it is possible to run the fans extremely slowly and still give them 12V. UK Mains works at between 220Hz and 240Hz so a fan rated at 125cfm/220Hz would still push 62.5cfm at 110Hz and 30cfm at 55Hz. Because most fans need 5V or 7V to start them and/or keep them ticking over, voltage based fan controllers can never drop below this level (about 50% so they can usually only ever slow a fan to 50% speed). Optimally, get yourself a T-Balancer, which is a fully automated PWM controller and does it all for you.
The key to a good quiet setup, in my opinion, is to get a set of powerful fans and run them slowly or intermittently. Let's say that my case is adequately cooled by 2 x 7V Akasa Ambers (30cfm each). Disregarding losses (which is naughty), I am moving 30cfm through the case. Two YS-Tech 125cfm fans running at 60Hz on a PWM controller will move that same amount of air and they will only be spinning at 700RPM! The Ambers will still be doing over 1000rpm. So, if I'm typing into Word the fans are quite often off, with the CPU fan providing adequate cooling and when playing BF2 the fans run harder and harder as the heat increases. As I'm wearing my headset (MEDIC!!!!) I can't hear them.