I put the DX pipe on with the 1.75 cores, and found that the volume level was not much more than stock but was deeper in tone. Fullsac indicated that the 2 inch cores weren't that much louder than the 1.75's, but would have a much deeper sound. I put the 2 inchers on, and can definitely confirm that the sound is deeper (better for me). The 2 inchers WERE louder, but not by a lot - especially at cruising gears/speeds. The improvement in tone quality over the very slight increase in volume was worth it for me in going to the 2 inchers. I can always throw the 1.75's in for a longer trip - takes about 15 - 20 minutes to do it.