I'd like to replace a couple of fans in my shuttle, a 70mm and a 92mm. they're the fans that cool the cpu, using shuttle's ICE system. They both have 4 pin connectors so they are speed controlled according to temperature. Can anyone help me with which ones i should get to replace them (from scan)? I'd like them to be as quiet as possible but strong enough to cool the cpu.

Thanks for your help.