Questions before the project starts (e_maxx)

[RC-Monster Mike]

Got any dimensions on the Lipos? 6s at 5200mah should be just fine with the proper gearing. Fitting the cells would be the main problem(potentially, though I am not sure the actual dimensions of the pack).

Get a real servo saver(like the UE) and your wioll get some steering. The 645 is OK at best, but you don't need two servos for steering. Just get a stiff servo saver and feed the servo 6 volts and you will have nice steering.