The Visualizers file goes to <userpath>\Documents\houdini16.0
The 3DSceneColors.Dark file goes to <userpath>\Documents\houdini16.0\config

The Visualizers saves some settings from the 3D viewport settings display (D), but I'm not sure if all things will travel to a new H16 install.

USe at your own risk, and be sure to save any original files before using the ones from the zip ;-)