An unusual design that I have never seen before, is this of your own creation or is there a 1:1 IRL? ...it makes me think this is an underground hauler with it's low profile.
You may want to incorporate some brass bushings within your pivot points for reduced wear & easier movement... like oilite bushings in the Tamiya kits would work great.
What's the reduction on your chosen axles? You may need to add a planetary reduction to the motor to propel those massive tires. I'm sure you're aware of the choices offered by RC4WD.
A great start on what I'm sure will turn out to be a mighty hauler.
