So was riding today and all of a sudden the exhaust was extremely loud on the 2017 Z500, thought I lost a spring or two. Not the case, inside the heat shield the exhaust pipe broken into two pieces. Easy enough to remove, could not get the oxygen senor to come off however. So, replace with factory exhaust or aftermarket? First time for me that I am looking for a replacement part, machine has been great with no real issues up to this point. Tried searching the forum for this topic and not too much came up.