Well, if you have dirt on your stuff, adding a rough specular to whatever is shiny will help it tons. Also, like I said, it doesn’t have to be highres, if the diffuse is 512x256, you can use 256x128 or even 128x64. Of course, the lower you go the less detail you get but still, the overall impression will be there and help make it look better.
Looking forward to the images 







