It is a well trodden route fitting a decat exhaust on an impreza wrx but the sports cat option is less frequently chosen. Probably due to cost more than anything else.
This 2004 impreza wrx had all 3 cats removed but the main downpipe cat replaced with a sports cat. Fuel pump fitted and a panel filter and that was it. No fuss, no dramas but it hit a very comfortable 285 bhp on Roger Clark Motorsports dyno yesterday.
I ran the car on the dyno to give a before and after figure for power and torque.