If you have a tanned skin for v4... why not open the texture map (usually found in Studio>runtime>textures>...) in an image editor and adjust the colour levels or brightness until you're happy with the colour? Then go back into Studio, apply the tanned map, and use the surface select tool to substitute in your edited version. Or, If you're feeling really cocky you can start editing the texture map names in the .pz2 files (Studio>runtime>libraries>pose>...) to call up your own maps.