Ok so here is my idea. I dont know if it has already been done or not but i am one of those who like having a loud exhaust sometimes but then other times i like having a quiet subtle exhaust (Bother performance of course). Like Magnaflow Vs. Borla. So i was thinking about trying to fab up a y pipe that the 3in in would split into two. In both side of the y would be a valve of somekind that would be wired to a switch so that when one is closed the other is open. One side of the y pipe would lead to the louder mufler, and the other would lead to the quieter of the two. However im not sure what kind of valve i would use and that would work with an electric actuator.
Again im not sure if this idea has ever actually been done or not, and if so what is it called. Let me know if anyone has any ideas on how to make this work.