I suppose its a similar design to the standard box, but it fills the gap in the bumper, which was what i was really looking for. I'll try and get a better pic in the morning.
Soundwise its only slightly louder, but it is deep right across the rev range.
Performance wise it feels a little more responsive than before, so its a bonus.
I did think that 1 hour fitting was a little long, and got a little worried when he got the spot welder out!
But he did a good job on it for sure.