Good Fan Type For Radiator

Solution
As said above those air flow optimized fans would be a downgrade, they are meant to push air through open spaces not radiator fins. The fans that come with the cooler are static pressure optimized, great for pushing air through the radiator fins. Corsair SP fans are generally pretty good, no need to replace them it certainly wouldn't be worth the money.

Dunlop0078

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As said above those air flow optimized fans would be a downgrade, they are meant to push air through open spaces not radiator fins. The fans that come with the cooler are static pressure optimized, great for pushing air through the radiator fins. Corsair SP fans are generally pretty good, no need to replace them it certainly wouldn't be worth the money.
 
Solution
You may want to use the software to fine tune the fan speeds(set a max or change the curve based on temperature). 2000 rpm fans may be loud for some users. This allows some users who find them too loud to still use them without too much temperature increase.

L(sp140l) version SP fans are not build like the normal SP fans, they are not as quiet, but you may as well see how the work for you.