Yeah its nice and loud under load and burbles on idle. The best bit of it is to shove it in manual, and with 50-100% throttle on change up between 4000-5000 rpm and hear the bangs! Came back from Brands Hatch via the Dartford tunnel the other week went up and down the box having a hoon lol, i guarentee it will bring out the big kid in you! I have managed to make a chav drop his food as he came out the chippy by popping the exhaust LOL.
Let me know what you think to no backboxes, must admit I am tempted to remove mine and go straight through. When the manager of the place came out when i had it fitted he saw the little box and said "you're brave!" but when we fired it up it wasnt as loud as we expected it to be. I guess thats the supercharger and turbo quietening it down!