Additional fans for my case 120mm or 200mm

[ShadeOfLife]

Hi,

I have a CM 690 II case. with i7 ( currently on stock cooler which will be changed when i will do any OC ) and MSI Twin Frozr III GTX680.

By default my case had back front / back and upper fan ( 200mm one )

My question is what kind of fan would be better to install on the sides.
Im thinking between:

2 x NZXT FS-200 Enthusiast Silent Case or 2x Noctua NF-P12

im wondering which one will create less noise of air going through side panel's holes as well as performance wise and reliability. Im not silence junkie ( i know noise level wise they both very close ) but i had crappy experience with side fans which whistled there.

I replaced back fan with Noctua NF-12 so i know its a good one but still not sure which will prove better on two side spots

Also should i install another front intake fan to have more air sucked in ? Im open to any idea's / experience with side panel fans you guys had

 

[amuffin]

The top fans are 140mm. Those NZXT fans are proprietary for their cases.

 

[ShadeOfLife]

amuffin - it seems you are correct. Then my question will slightly change between

2x Noctua NF-P14 or 2x Noctua NF-P12 on side panel as both are in same price its just matter which will create less whistle.