The stock silencer or catback exhaust system with part number 4T0.251.051.F is a special exhaust for country like China to meet higher emission standard. This exhaust has four massive OPF/GPF/PPF thus resulting a very quiet exhaust sound, I choose to delete these four filters, here is my exhaust video after modifications, the volume of the sound and the pitch of the exhaust are finally recovered. This exhaust is a chamber muffler design and piping is much longer when valves are opened, so the exhaust sound pitch is much higher compared to the stock EVO non gpf version.
BTW, I am based in Shanghai China, please contact me if you are also in Shanghai
I wish this information might be helpful
BTW, I am based in Shanghai China, please contact me if you are also in Shanghai