FoaS's "signature" I believe. Feel free to correct if I'm wrong. 
Short response: It's not really a "Signature" but something that I just enjoyed changing.
Long response: I always enjoyed GAFY's Federation textures, the ones that also had the blue in them. However, there were just a handful of things that I wanted to change. As you can see I embraced the Blue paneling (which was really meant to be the visual pusher for the retexture line, no the orange grilles). I originally wanted to go with blue/purple grilles, but I found that the entire thing just looked too cold, too much blue. I then just looked at my color wheel and picked Orange - due to high contrast it has with the blue. I ran with it.
What I would like to think of as my signature is the Fractal Flame patterns in the grille, not the color itself. the Juva has them, too. :-).
Yea I'm not sure if there's a reason for that (later era upgrade) or if he just does it because he wants to. I don't really care, it's something different and the rest of the texture is such a major boots over what we had previously that it's worth getting even if you don't like the orange.
It's not an upgrade or refit or anything. I often speak of the FoaS-verse. These are from that, thats all. Sort of like my own timeline where I can do what I want to trek history. Trek is a salad bar: take what you want, leave the rest - I just brought my own dressing from home.
Anyways: Starforce. The conversion looks great :-)
