Live in N.J., an inspection state. Running Kooks 1 3/4 with catted X pipe.
My 02 sensors are turned off, wouldn't pass inspection with them on
Most, if not all, high flow cats will throw codes. Have a set of Kooks " green " cats on order. I see no other way to get past the emissions test.
Can't comment on the sound level as I'm running the stock mufflers.
...................( not interested in noise, just hp. )