@kartoffel, one thing about the ground normal map... I assume its generated, you might want to take the source texture and darken the lines betweent the tiles, that way when the normalmap is generated it considers those lines as "deeper" it will give a more realistic effect. and look less like just noise.
I never use 100% generated normalmaps or heightmaps. (especially generated heightmaps suck)
The normalmap is generated from a heightmap (done by hand) and mixed together with a normalmap generated from the actual texture to get some more fine detail.
I usually do it like this with all my textures.
But indeed the specular reflection looks like it's just some noise normalmap.
I think this is caused by the high specular exponent I was using there.
