whats the limit on batt cells?

i think i found the batt is this a good spec?
Capacity: 4000mAh
Voltage: 2S1P / 2 Cell / 7.4v
Discharge: 25C Constant / 30C Burst
Weight: 235g (including wire, plug & shrink wrap)
Dimensions: 137x45x25mm
Balance Plug: JST-XH
Discharge Plug: T-Connector (Deans Type)


do u guys thin if i run 2 of these ill be good?theyll be on this sav.