i just installed my bassani o/r x and catback today and it has a "crackles" sound that i can hear coming out the tailpipes. how do i get rid of this? will the mufflers break in and smooth out? do i need to add cats? this happens in various rpms in different gears and speeds. at certain rpms it has a smooth exhaust note that sounds amazing, then it goes right into a crackles sound. i have yet to hear someone drive my car so it may not sound all that bad from the outside. any advice to make me feel better about my new exhaust?