Well if it's one of the cats that doesn't have a sensor in it then you don't have to replace it. These cars have four cats and you can remove two of them and still pass emissions no problem. Down side to that is the car will be a little louder but it's not a bad loud or obnoxious loud. A new cat will most likely run you about 250-300 for a replacement or you could get a Magnaflow cat for I believe around 350 and it will sound even better but then you should replace all of them if you go that route. Sorry for all the ranting.