I think its good though mate.. i actually kinda like the low quality background, its obvious you're going for a gritty streety graffiti look.. just make your writing graffiti style and i rekon you've got a winner there.
Also, try a 1pt black border around the edge. I never used to but i think it makes all my sigs a little bit better... see what you think
the "This occurs after you have posted 5 messages on the forums. Your account will be automatically upgraded to 'Newcomer' within the hour, unlocking additional features such as posting links and more." message wont go away