seriously, i REALY REALY liked your render, one of the best(IMO) render of FZR with custom lights. great job dude.


i see just roof and lights 






. And if you finally find a material that looks good and than change anything in the light setup or so it´s totally messed up again
.
what it "sees" and in your scene, a large portion of the right side of the entire render is black/very dark. So, the materials looks different (depending on how reflective the material is - in this case its rather reflective) - try adding a light there, to shine the area up, and see how the rims etc will be affected.
Lower the rendering quality if you have to.