The rear muffler determines the sound and the design of the outlet. It offers the best balance between what you spend and what you hear: at the same diameter, the body volume and baffle type distinguish a deep tone from an unpleasant resonance at 2,500 rpm on the motorway.

Keeping an intermediate muffler eliminates precisely that resonance. Removing it makes the car louder everywhere, including where you did not want it - this is the most common regret after an exhaust upgrade.