[jimmy]

I thought unless the guy is using a wiperboard speed controller and a mabuchi 540, then two servos was against the rules.
You aren't allowed to have more plugged in - unless this has changed - in which case it opens up a lot of options for many new designs . Micro servos adjusting links or somehow stiffening the outside dampers during hard cornering. It's a free for all if it's true that you can run more than a steering servo.
Advanced electrics braking each of the 4 wheels individually to maintain stability and enable faster cornering like the prodrive car - gyro for counter steering, flip-over mechanism to put the car back on its wheels quickly if it rolls. Engage and disengage the actions of a centre differential.