The CSC sounds very nice on the 156 GTA. I have the back box and it just adds a bit more rumble. It's not overly loud or intrusive and is not noticeable at cruising speeds. Just makes the V6 sound lovely when you boot it and looks great.
Joe, are you following me? Q2, then CSC, I hear you're going to get a detail from Roy.......

Must be that great minds think alike!
Cheers,
Nigel