[Patrick]

The twin diff thing looks interesting. The thing I would be worried about though is if for some reason one motor (say motor #1) doesn't start up (cogging etc) as soon as the other (motor #2), and instead of it driving the car forward it spins motor #1 in reverse because of the diff, then motor #1 tries to start up while spinning in reverse, which can be bad for the esc. I burnt my year and a half old quark by hitting the throttle while still rolling backwards. Don't know how much chance there is of that happening, but something to consider. The thicker the "motor diff" oil the less chance of that happening. And obviously use exact esc settings.
That made sense in my head, but not so much in writing.