Yes, this is a Cusco piece. They just came out with it and they do make one for the Impreza. It's an add on for your existing rear strut tower bar and goes for about $150-$175.
They just came out with it so I don't think anyone will have them in stock here in America, yet... And remember, you need the Cusco Rear Strut Tower bar to use this piece.
You should be able to order it from your usual Cusco source (us, ISR, Teague's, Nativo, JC).