MMM/2200 on 6s would be crazy torque. You could go that route or even just spend a bit less and head to hobbypartz.
http://www.hobbypartz.com/77p-sl4400-2s1p-30c-2222.html
or
http://www.hobbypartz.com/77p-sl4000...-hardcase.html
* These have been comparable to Turnigy and Gens Ace for me and there a bit cheaper. But see how the leads need to exit your battery before buying a lipo.
http://www.hobbypartz.com/thac6smbachw.html
*Great charger and no power supply needed! AC or DC powered
http://www.hobbypartz.com/07e-c-combo-m1.html
*These are great on 4s (2 x 2s lipo)
or
http://www.hobbypartz.com/07e-c-xerun-80a-sd.html
&
http://www.hobbypartz.com/96m802-4074-2150kv.html
Tacons are great and cheap. Same with the XeRuns. Im only suggesting a 4s set up becouse you'll still reach 40+mph and it wont shread your drivetrain.
But browse the site. They have 150A set ups and 3s packs to run 6s. But if you plan on that make shure your diffs and driveshafts are up to the callenge