the only thing i think needs to be changed is the little piece of his right eye on the left of the signature. just cover it with black so it looks like the frame is covering his whole eye or atleast shadow. it kind of draws my eye.. i dont know why lol.
I think this is a very nice sig indeed, give it a 9 outta 10, composition is nice shape of the vectors and nice and it keeps the colour all the way through the sig, I think there is nothing that needs to be touched. Dan.
I really like! Maybe use the burn tool to add a little more detail & blend the render with background a little more.