Out of the box only the front wheels of the model steer. These "arm connectors" effectively make the model have four wheel steering, but interestingly don't actually say that on the packaging. Only the lean of the front arms is transferred to the back, not the steering angle. The steering angle is a secondary effect of the lean.
It's not exactly an upgrade, but the kit comes with a
thick paper board which can be cut and folded into a wedge.
Installed in the roof, this wedge allows complete forward rollovers.