Black, these are some mighty engine glows that make me pale from jalousy.
The shape is cool, did you have any function in mind for the « transparent circle »?
My only advice would be to add more complexity to the texture, bt how to do it in Blender??? In vue quite easy...
Talv: I am working on cityscapes right now, as an idea. But random is good for me, and weapon will probable look like a death star

(see my entry for beauty).
PS: we can keep the capital ship thread open inthe archived LTFC if someone wants later to add a creation...