I have the same impreza as you. I have a full exhaust on mine. Uel Borla header, Rallisport hi flo cat, greddy ti-c catback. It's sounds amazing but personally I wouldn't even bother unless you have a wrx. I got the exhaust last summer. During the winter I got a check engine light and it hasn't went away since. I put a spacer in the after cat o2 sensor but the light came back. The code is a p0240. Catalytic efficiency below threshold. Which means exhaust. So if I was you I would just get a nice set of h&r coilovers, a nice set of rota wheels and you will be happy as a pig in *****.