For starters, ditch the axe. While it might seem like a good idea, it's really just wasting weight.

As for motors, 2 LEM-130s powered by 11x A123 Battlepacks should cover it.

Hardox can only be made as thin as 3.25mm. I would suggest replacing your current armour with that.

Here, I'll help you with the description of the Drillzilla crushing jaws:

weapon: A pair of crushing jaws, each which looks like the one used by Suicidal Tendencies, powered by a Vivoil Pump and LEM-130. Each jaw has a 3:1 ratio giving it 9 tonnes at the ram and 3 tonnes at the tip.