its real mellow at idel. but when you get the rpms above 3k its pretty loud. its a lot different sounding than 5.0 with the same type of exhaust setup. these 32v motors just make a different sound. i like it and my friend with a 04 mach has SLP exhaust and high flow cats and i think its just as loud. i like the way mine sounds compared to his. i think a high flow cat would tame my car down noise wise a little more i just went with the off road x because it was cheap and easy. but i did buy the MIL eliminators and now i got $200.00+ into the mid pipe!