I want speed!

[RC addiction]

i have a bl rustler (novak 4.5) not fast enough. i have taken out as much weight as possible and are currently running 2s lipo. i want to be able to double up on my batteries, meaning use two 2s lipos for speed runs and be able to go back to one 2s lipo for the track. i've searched the threads and got alot of useful info but the more i read on the more indecisive i become on a combo bl esc controller and motor. help me out guys i want to be able to run 50 mph for more than just a few passes with out cooking anything, thanks!