i am running yoko 8x2 mod motor on mine !! with 4cell GP3000, it gives a bit more than 6 min run time. however, i also noticed that the servo action is not as smooth in the last 3 mins before the batt dump .... i am now using a 6v FET servo (KO 2004FET), i might switch to a normal 6v servo (Futaba 3003) to see if this will improve.
ps : i already install a 1000uF cap on the rx bec.