Here is some information I could compile...
Batteries: The HT model uses two NiMH, and each is rated at 72V 350W/hr. The PT has higher density, might be LiPO I can't recall, The batteries have energy monitoring over I2C, and a secretive measuring system. The batteries are recharged partially by regenerative braking. The batteries are sealed against moisture. The batteries last 500 cycles, each cycle gives ten miles range, and cost $600 a set.
Motors: The traction motors drive each wheel through approx 100:1 gear reduction and are rated at one horse power each. The motors have two identical but isolated sets of windings and are linked to two identical controllers.
Controllers: Two identical three-phase controllers. Fully redundant. Can operate together (for 2hp peak per wheel) or operate on one controller (failure protection). Based on a TI 32bit DSP, 30+ megaflops/sec.
User interface: Original model has a twist grip with hall-effect sensors (two sets) for steering and a dual port LCD. Later model has a pivoted steering column for steering. The LCD and steering talk over dual redundant CAN buses.
Gyros: There are five, with dual redundant cross-linked pairs driving separate DSP controllers. There must be software parity on gyro data to process a motor engagement.
Overall there are eight or ten Microchip microcontrollers, plus the two TI DSPs. On five (?) PCBs. Which interconnect to form two electrically isolated (but optically or magnetically linked) systems.