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: with the same diameter, the body volume and baffle type separate a deep tone from an unpleasant resonance at 2,500 rpm on the motorway.

Keeping an intermediate muffler specifically eliminates 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.