SpeedIsLife I too have the MBRP 3 inch XP with long tubes and HF cats ( M 6 LS3 ). Doe's yours have the resonator center x pipe or the X pipe without . I have some drone at 1700 to 1900 with the X pipe center section . I love the very deep hollow sound with no rasp of the MBRP ,but could do with less drone between 1700 and 1900 .