https://www.bigcitythunder.com/ If you can get a baffle from big city thunder to fit anywhere inside your exhaust pipe, it will drop the DB level about 7 to 8 db. I had a DRZ racing super moto that was waking up the neighborhood. I measured the inside pipe diameter in front of the slip on, ordered the closest baffle size, and installed it in the pipe. The baffles have a set screw hole, so when I had it in place I drilled a hole through the pipe and installed a set screw with lock tight. I have gotton baffles from Big City Thunder and used them on
three different bikes. None of the bikes I used them on were listed in their applications for my bikes.
These were all racing machines that were too loud. The sound changed for the better, de-accell popping totally stopped, and the dyno follow up showed some low end improvement with very modest top end loss. I did not have to re-mapp these bikes. Find a straight section of pipe anywhere after the header and call Jim at big city thunder to get the closest fit. You might find two baffles to put one in each slip on exhaust? Thess baffles are very affordable, $60 range.
Keep us posted if you go this route. I am just now starting a 2007 FZ6 to maximize low and middle RPM performance.
The statement from Danmoto about head pressure and heat is off base. Your stock set up probably had triple the back pressure.
Dennis, near Chicago