This principle is only applicable to turboswhen the unit is closed the exhaust is routed to your normal set up and when it's open it dumps right out the athmosphere before the cats, any turbo tuners (Lingenfelter or Duttweiller) will tell you that there's no such thing as a big exhaust turbos hates backpressure. Again, a good welder and a good quality unit (billet) will make this car a road monster at will.

 

If your Mercedes Benz car engine is running without a muffler, you know what a huge difference a muffler can make to the noise level. a muffler is a part of an exhaust system. My Mercedes Benz muffler is well designed to decrease the volume of the exhaust.