SLN BMW S58 M3 G80 M4 G82 & X3M X4M LCI 4.0" Resonated Single Mid PipeSLN Performance G8x Series 4" Resonated Single Mid pipe with extended underbrace Welcome to the SLN 4" S58 Resonated Single Mid Pipe for the G8x platform. This is the largest bore mid pipe on the market with a resonator that actually works. This will be for the person who wants a little less noise and aggression than the non resonated version. The quality and fitment of this product is truly world class. Features Significant power gain True 4" Single