ST-R Brushless Help!!!????

[str8up]

I am in the process of setting up my brushless ST-R and i am stuck on a motor to buy and a cell count to run it all.

Here is my setup so far-
MM ESC
3 cell MaxAmps Lipo 5000 mah 100 amp cont. 150 sust. 250 burst
Nomadio TX/RX (has telemetry so a ubec or lvc is not nessacary for me) (will run sep rx batt to power servos)
46 tooth kyosho plastic spur and the stock metal 52 tooth
stock diffs

My qustion is what motor to get and what pinion for the motor and if my battery will run it all efficiantly?

I am looking at a Feigao 7xl with 13 tooth pinion?????????? With the batt i have now!! I would like to keep the lipo i have now but will upgrade if it is not enough and if the esc can handle it?