Gray quads

Hi,
my model looks good in Blender and 3D Coat but it has some strange artifacts in Unity: many quads look grayed out... why is this?

This is in 3D Coat or Blender


This is in Unity's Standard Shader or Bumped Specular


This is in Unity Specular shader (so without normal map)


And this is in Bumped Diffuse shader (so without specular)


Am i missing some shader setting?
The Unity project i made for a test is zipped in this file spaceshooter.zip : https://onedrive.live.com/redir?resid=5FCA816C7345298E!255
please can you check it out and find the wrong shader settings?

I can't figure out what's wrong with them or if the issue is with normal/specular maps but it's unlikely bc they look good in 3D editors.

Thanks a lot!