i can't deside 5s or 6s?

[gizzmo79]

I have a self made truggy, it running with the mamba monster max and a lhener 1500kv motor, i'm about to get som new lipos but i cant deside if i'm getting 5s or 6s. i'm thinkink about the new hard case lipos from thuner power 5s (2s+3s) 4200mha 40c, with a total of 250usd or the hardcase 6s(3s+3s) 2600 30c mike is selling to a total of 250usd.
What do you guys think, who should i get?