Yea I can't say anything other than what has been said. I would do a 2px border and a light source coming from the bottom of the sig and its good to go!!!! Great job, I actually think I would keep it black and white!!
I would have to agree with the rest border is a bit thick. A suggestion i have to help improve your borders is to apply the image on a new layer, go to blending options, stroke choose a 2px and choose inner and bam easy as one to three lol. Ohh and one more thing im not sure if its just me but there are lots of lines by the renders cape. Im not sure if thats part of it or part of a wireframe. my suggestion is to remove the lines but its optional.
In the original the border doesn't actually go all the way around it is only at the top and bottom, but i can see how it would be a bit to much. But I would have to say most of the sigs I've made have 2px borders.