Letting forum users know that I had a mechanic spend 3 hours and he fitted Black Widow exhausts on my 2016 GSXS1000F, and he used the OEM muffler so everything looks legal from the outside. They cost $600 Australian dollars delivered. They are really nicely made in the UK. The result- absolutely brilliant.I have got rid of all the shackles forced on motorcycles by the EU fascists and the note is outstanding. Warming up and trickling along they don't emit anything to annoy the neighbours, but when you open the throttle, the sound is fantastic, deep, throaty and no louder than a dickhead on a standard Harley (you know, the grown up guys who used to put a bit of cardboard on their back bicycle wheels with a peg). So don't be put off by the armchair critics, they are a third of the price of the Yoshis, and look identical; the welds and finish are great. Just a note of warning, my brother bought some for his 750 GSXR Suzuki, and had a lot of grief trying to do it himself. If you can afford it, pay an expert to put them on. How good to park all that unnecessary metal work down in the shed.