Isn't it KKS who make the electronically switchable set of back boxes? I saw a few videos of it and it looked fantastic. A button mounted in the cabin opens and closes flaps in the exhaust. Closed and it sounded stock, no drone etc.. Open and it was akin to the rpi stuff i.e. intoxicating but annoying for prolonged periods. Trouble was it was an extortionate amount of money to just get a really nice sounding set of back boxes with convinience and little to no performance improvement.