We have installed the 42443's on probably about a dozen customer cars now, and they are all thrilled. With the 3rd cat & res, w/o the 3rd cat & with res, and w/o 3rd cat & res all sound great. The "Original" 40's are a lot louder, and with no 3rd cat & res it borders on obnoxious. Haven't tried the "Super" 40's yet, but I might put them on my '97 once the motor is done just to see the difference.