The trakpowers are about 5k
Heres a link, keep in mind they are 20c batteries and thay can hold over 3.5v per cell on a 100amp load, which is very good. I always try to buy batteries that can provide much more than my system can draw, cause you never know what can happen!
battery:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXRWF7&P=ML
balancer:
http://www2.towerhobbies.com/cgi-bin...?&I=LXRWF8&P=7