I removed the centre box from my 2wd saff and it sounded awesome, with no noticable drone difference inside the car, but when i did the same on my 4x4 ( different manifold ) it was terrible and the drone was unbearable so it got put back in.
I removed the rear box on my Esc cos as they cant be seen like the saffs can, the noise was lovely and no extra drone!!
Hope that helps.