Is the sport manifold still the original one? is it only the rear silencer that is in question? How long have you been driving with the original muffler in 2018? If I understand you correctly, you want a throaty but socially acceptable sound. My experience with various exhaust systems is that they only develop their good sound after about 3000 km and also become somewhat louder. It could be exactly what you are looking for...if you have only driven a few km with it.
