Prior work suggests that rubber-containing polymers like impact modified polystyrene (HIPS) and thermoplastic vulcanizates (TPVs) exhibit unusual behavior when injection molded to create parts with microstructured surfaces. This work was an in-depth investigation of the effects of material composition, including matrix stiffness, rubber content, and rubber domain size, on replication of injection molded microstructured surfaces. Multiple grades of HIPS, poly(acrylonitrile-butadiene-styrene), and TPVs allowed for a range of material properties. The nickel cobalt tooling inserts contained features with diameters of 20 um and depths of 20 um. The polymers were molded using a range of processing conditions (melt and mold temperatures, packing pressures, and cooling times) and replication was measured using scanning electron microscopy and profilometry. Microfeature replication (feature definition and depth ratios) was correlated with matrix stiffness, rubber content, and rubber domain size in the polymer materials and with the processing parameters.