i live in ok. and have not had my cat'* in my gto since i bought it new and had the shitty exhaust cut off. i now run a 3 1/2" custom mandrel ben exhaust built with the dyno max race muffler, the only one that makes a muffler with a 3 1/2" inner diameter. i get stopped by the hwy patrol quite often and have never had them say one word for not having a cat. they just say that my car is sure healthy and bs and leave.