Wide color gamut such as BT.2020 allows pictures to be rendered with sharper details and more vivid colors. It is considered an essential video parameter for next generation content generation, and has recently drawn significant commercial interest. As the upgrade cycle of content production work flow and consumer displays take place, current generation and next generation video content are expected to co-exist. Thus, maintaining backward compatibility becomes an important consideration for efficient content delivery systems. The scalable extension of HEVC (SHVC) was recently finalized in the second version of the HEVC specifications. SHVC provides a color mapping tool to improve scalable coding efficiency when the base layer and the enhancement layer video signals are in a different color gamut. The SHVC color mapping tool uses a 3D Look-Up Table (3D LUT) based cross-color linear model to efficiently convert the video in the base layer color gamut into the enhancement layer color gamut. Due to complexity concerns, certain limitations, including limiting the maximum 3D LUT size to 8x2x2, were applied to the color mapping process in SHVC. In this paper, we investigate the complexity and performance trade-off of the 3D LUT based color mapping process. Specifically, we explore the performance benefits of enlarging the size of the 3D LUT with various linear models. In order to reduce computational complexity, a simplified linear model is used within each 3D LUT partition. Simulation results are provided to detail the various performance vs. complexity trade-offs achievable in the proposed design.