Wait, I'm confused. How the heck did you guys get to parallax mapping? Height maps are just a black and white map. The most common use is to use them to create a bump map. You can also use a height map and a normal map to create a parallax map, but that is a completely different thing.
We use normal maps on a lot of our props. Normal maps are a more complex version of bump maps, and look a lot better. As we go through and polish up the mod, we might redo those textures you are talking about and add normal maps to them if they really need them.