man, I couldn't find specs on the stock ESC or the stock motors.
The redcat 1/8 crawler is similar size and uses 100 turn brushed motors. And it's ESC I don't think can handle less than 50t motors.

I think you could get away with using a 7.4v 2s lipo battery...which would add some wheel speed.

The RC4wd outcry duel motor ESC can handle a pair of 35t or high motors...and run up to 4s lipo! It has drag brake and turbo BEC. Only thing it does not have is LVD or waterproofing. Otherwise, it is a good ESC for the money
I had one on this rig I built out of the exceed mad torque 1/8:
http://www.youtube.com/watch?v=p2THABa7G3k http://www.youtube.com/watch?v=TWZoW-OnVgQ