The HKS axle back exhaust is the same as the Mazdaspeed. It starts to really get loud around 3000-4000 rpms. I'm 19 and the sound is still unbearable for me, but its better than the wahhhhhhhh or fart sound. It came with a silencer and hopefully that will tone it down a bit. I JUST DON'T LIKE THE WAY A SILENCER LOOKS THOUGH lol 
