Due to their deterministic behaviour, compliant mechanisms are well-suited for high-precision applications. In this paper the benefits of redundant links and actuation are investigated in terms of increasing support stiffness and homogenising actuator loads. The manipulator is modelled with lumped inertia properties of the links and non-linear relations for the joint stiffnesses. The lumped parameter model allows a fast system level performance optimisation of the joint geometry simultaneously exploiting joint pre-bending and preloading, where the stiffness matrices of all joints are computed numerically efficient with non-linear flexible beam elements. This model is applied to optimise the design of a compliant and redundantly actuated 2-DOF 3RRR parallel kinematic manipulator. The improvement of support stiffness is demonstrated with an analysis of the first parasitic natural frequency. Balancing of the actuator torques is concluded from a potential energy analysis.