BMW F80 M3 & F82 M4 S55 Equal Length Midpipe & Under BraceWelcome to the BMW F80 M3 & F82 M4 S55 Equal Length Resonated Exhaust Mid Pipe from SLN Performance. This is the best value solution to the F8X sound problem. For years enthusiasts have wanted to find a solution to the buzzy and raspy sound these cars produce from the factory. Since these cars were released back in late 2014, we all knew there was world class sound lying under all the rasp. SLN's mission has been to find this hidden sound and allow