Been playing around all day, here are my findings.
• Stock cooling.
• Added a single 120mm Spectre Pro fan in front of the PSU blowing air down and out, also bringing air in from underneath.
• Three 230mm Spectre Pro fans fitted and running, the 120mm disabled.
• All fans running.
i5 2500K@ 4.5Ghz
Antec kuhler 920 set to Silent mode.
Palit GTX570 with factory fitted twin fan cooler @ stock frequencies.
Ran Prime95 for 20 minutes.
Ran Heaven 3.0 with the same settings as in the results thread -
http://forums.overclockers.co.uk/showthread.php?t=18386056
So as you can hopefully see, adding the 120mm fan bringing cool air in knocked a few °C off, and all the fans running dropped the temps on both the GFX+CPU.
Pros
Looks so pimp
Lower temps.
Cons
Noise, its definitely louder with these fans than it is out of the box.