In Cheetah-cub-S we realized an efficiant concept by implementing a spine-like structure with one DoF into a quadruped, modular and mobile platform. We increased maneuverability dramatically compared to a robot with rigid spine, while keeping controlling effort low by using intelligent mechanics. Therefore, it is possible to steer via trunk motion without changing the gait or corresponding parameters. The robot weights 1160 g at 0.1 m (height), 0.105 m (width) and 0.205 m (length). Based on qualitative tests, it is able to run 0.36 m/s and turn within a radius of 0.51 m (equivalent to 2.48 body lengths) at 0.31 m/s (equivalent to 34/s). Furthermore, we could steer the quadruped around three objects in a 7.13 m (23 s at 0.31 m/s) slalom within our test area. Due to its modularity, Cheetah-cub-S is a versatile mobile platform and components such as the spine segment, legs, motors or steering mechanism can be exchanged.