Mtroniks... are you from the Uk fella?
The Mtroniks motor is basically a blue can feigao, a Nemesis unless its sourced from elsewhere (rather oldschool). Shame its not the the larger version with an XL can motor, but its a good basher setup if geared correctly. The Mtroniks esc is roughly equal to an MM, so something like 80-100amps rating.
What diffs are using exactly, its hard to tell from the pics?
What gearing are you running?
I would suggest loosing the comedy BigJoes in favour of something a bit more usable (yes, I am a hypocryte everyone..

)- something like stock 3905 rims and tires, or zombiemaxx rubber even (nice aggressive tread). That will reduce the stress on the esc and motor. The muchers are pretty good though, great for grass I hear.
Beyond that, it looks pretty sound.