Muffler?

Hi everyone,

I was looking for an exhaust muffler that has valves however I don’t want there to be a dump exhaust just the muffler by it self and the valves should be on the inside so it would look like any normal muffler also I don’t any type of wiring or vacuum pipes to the muffler the muffler should be able to open the valves inside effectively turning it into a straight pipe by it self when it feels there is pressure and close by it self when there is no pressure. If anyone has any knowledge about this or can be of any help I would grateful thank you. If ur asking why Im looking for such a muffler it’s because of tight modding laws in my country. So fly under the radar is what im trying to achieve.