single 4s or.....

[kneedeeppow]

hey guys
i have been running a 4s 5000 in my mbx5t and getting 13-14 minute run times. am moving on to a rc8t and thought now might be the time to explore other avenues of power sources to try and break the 15 minute plus mark(to compete in finals-if i every make one) would running 2x 2s 5200s give anymore than a 4s? am running mmm v3 w 2200kv,would the mmm handle 2 x 4s?

cheers

pow