SLN BMW S55 M3 F80 M4 F82 Equal Length Resonated Mid Pipe with underbraceSLN Performance S55 Equal Length Mid pipe M3 F80 M4 F82 (Resonated) with extended underbrace Welcome to SLN S55 Equal length Mid Pipe for the F8x platform, or in other words, the 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 the late portions of 2014 we all knew there is world class sound lying under all