I use it with WSE2 on DX9. Ever since the WSE2 switch forcing DX9, the game now renders some specular lighting or shading even on the lowest settings. Being partially colourblind, I have a hard time seeing the default textures in some maps as they're dark and blend in with the environment and armours, especially when it's night time. The heirloom pack makes every weapon brighter and much easier to see. A slight performance hit FPS-wise, but I play better with it.