RE: will i burn my motors /ecs with this battery
The ESC is the choke point. Most motors will handle a few more volts than rated by the vendor (they know R/Cers). If the ESC can handle four cells and you can keep the amps in the proper range, you can probably get away with the four cell packs. You may, however, shorten the life of the motors - but it'll be a helluva ride until they die(-:
Walt