I have the Haywood and Scott System (de-cat centre & back-box), still has the nice Impreza burble but isnt loud at all. I opted for the small silencer in the centre section, think that was an extra £20 or something?
I put a down-pipe cat back in and it sounds lovely, makes a nice sound when you put the foot down. Also went for the round tip which I think looks miles better.
Thumbs up from me.