This Z4 E85 20i came in at DKU Performance for an exhaust system with REAR BACK BOX. Our client wanted to limit the sound of the vehicle and make it quiet and subtle. Since we are dedicated to providing you with all kinds of exhaust related services, we designed and fabricated a rear back on this vehicle. The exhaust back box is a rear muffler that has the purpose of limiting the sound generated by the passing of gas through the exhaust system. The custom work performed on this vehicle transformed the sound of this vehicle and gave it the most subtle and perfect note. We finished this transition by installing premium quality quad tips at the back. These chromium quad tips not only improved the sound of the vehicle but also enhanced the look of this BMW. We designed these quad tips by keeping their diameter 2.5” for the clear and subtle sound.