the fan info is on the Corsair website.
AF = case fans
SP = radiator/heatsink fans
the SP120 are the way to fan a radiator. depending on the audible question is how loud
is loud to you. the OE fans are in most cases too loud, the SP120 (perf edition) are a bit
quieter, but thats the end-users call. they do include a low noise adpater to slow the fan
speed and make them quieter. the SP120 (quiet edition) are easily quieter, but you may
have an increase of 2°-5° load temperatures.
i just use a simple push SP120 (perf) and undervolt to suit the audible concern. push/pull
OE stock fans in most cases is good for 2°-3° better than just 2-fans. but noisey as the dickins..