The soft rubber stock mounts flex excessively and in a tight engine bay, this can cause some components to rub when the engine is producing peak torque. In addition, when the stock mounts flex, they are effectively absorbing some of the torque produced by the engine. Get that torque to the wheels with stiffer polyurethane motor mounts! You will also find the car to be more responsive to throttle input with these new mounts, making it easier to maintain traction with good pedal modulation.
Please note that due to the stiffer material, there will be an increase in NVH. Some people will not notice the increased NVH, while for others it may be intolerable.