Hi guys, a quick update. I've finally got round to ordering the parts in order ro make custom back boxes out of the standard, unloved, 4200 items. My plan is to change all the internal pipe work, put valves on all 4 tail pipes (2 open and 2 closed) and Akrapovic Carbon wrapped tail pipes. Why 4 valves? Well, when the GS starts it 'barks' because the valves are open, ie they need vacuum to close, so until the vacuum builds it runs loud, and the quiet side is always open allowing some gas to escape. By putting closed valves on the loud side and open on the quiet side it will be quiet when it starts as it will allow ALL the gas to escape via the quiet side. When the switch is flicked, the loud side will open, the quiet side will close allowing ALL the gas out of the loud side. This will make the new boxes both louder and quieter. We can of course just put open valves on the loud side as per the GS boxes which will be cheaper. I'll put some video on when they are done. I'm hoping to have them made before we go to Spain so watch this space!