I did a CAT Turbo and removed the center muffler on my 2013 Mini Cooper S and it got loud. almost to the point where I cut the exhaust in half. after installation and about a month after it broke. he is still too quiet. even makes the Mini's punches and pops sound deeper in Sport mode. Is it louder than stick? - Yes, but not much. Sound under stock? - Yes, but not much. Sounds good - YES it does, you just want 75% louder. it muffles the sound too much but the title says it's ULTRA quiet so I agree.