i hate css -.- 1.6 better but the only problem your having is that you don't have a light source its just a solidly bright signature also its to sharp looking try to not sharpen and brighten the signature up alot keep certain parts dark and certain parts light to keep a good balance it adds a great sense of depth to it
Seems TOO BRIGHT and Blurred - Lighten the sig to just one area of blur, or possibly just blend the render better - Change the Light source to possibly the Shotgun / Render My 2 cents! Some minor changes here and there could clean it up a bit!