1 6000 mah pack or 2 3000 mah packs ?

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i have a agiator S with 2X feiago 540s.
wil it realy make a difference if i run 1 turnigy 3s 5800 mah 40c for both motors or should i run 2X 3s 3000 mah 40c ?
i dont have room for 2 big ones. so wil it make any difference ?

tnx.

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