I bought an HKS Silent Hi-Power cat-back and it sounds AWESOME. Mellow and deep. My brother says it sounds like a V8 at idle, but I’m not sure if I agree. It’s bassy for sure.
It also allows me to run more boost! I ditched the Cobb unit and got a custom street tune which has me running 17psi, which should be good for around 300hp and 320 pound-feet of torque.
Gas mileage has increased too! If I’m on flat highway I can easily average 32mpg.
http://www.youtube.com/watch?v=s4FcniO_odA