[GScivic7]

IMO everything OBX is garbage. Go with a carsound cat. They will make your car a little louder since they are free-er flowing, and should increase hp a little bit, nothing substantial. And every aftermarket cat i've seen is weld on because they are universal applications. You can have a flange made and welded on so that it will bolt up to your stock header and exhaust piping though.