Hi Keith,

> Is it possible to modify the texture properties of surfaces other than the diffuse colour?
> Can the sepcular value be adjusted?

Sorry no there isn't currently any way to separately adjust the specular color of an object, that's something that you would normally do in a rendering program instead of inside of MoI.

You can enable specular highlights on or off for the display though by going to Options > View > "Lighting options".

- Michael