I bought
these fans from Associated and they work really well. Dual 20mm's pre-wired so you just have to plug them in to your receiver. If you wanted to you could buy that fan kit and add a third, seems like overkill to me though. You can put dual 25mm's on the top if you choose, but you would have to wire them your self. Someone else might be able to speak as to how much performance you gain with them?