This engine mount heat shield is absolutely necessary when running rubber, polyurethane, or other polymer engine mounts. While designed for the E46 and E85 Z4, they can also be installed on E36 models and others that share the same style engine mounts.
BMW Part Number: 22111094624
Installation: the heat shield is simply sandwiched between the engine mount arm and the top of the right engine mount. It should be facing towards the headers/manifolds to deflect the most heat.