I would suggest a few things…Screws do not end up being turned to the exact same angle. I would rotate them to different directions. I would also use a grunge brush to rough them up a bit. I would also ask that you remove the texture from the wires. Against the textured background it is way too busy and the wires get lost in the image.

Over all this is a great image. Minor edits and you got a very cool image.