Put basssani cats on today and the sound is purfect ,just what I was looking for,its those metal matrix ones,i think thats what there called ,when you look inside its just a treated screen,looks like it will flow good and only around 3 hp lost.But it feels strong went for a test ride today and it was hot out and the car felt like I was driving at night with cold air.I was pretty impressed.Feels like i got more bottom end torque and couldnt really tell if i lost any power on top.Guess i'll find out at the track.Pretty happy with the sound its atleast only half as loud and although louder than it was with factory h-pipe and borla stinger cat-back..So it looks like i'm going to pass the decible level at the track and not have to get another cat back