My Abarth was fine with its crackly poppy goodness with its bone-stock exhaust; my Fiesta ST has stock cat and Aftermarket cat back (3" all the way back from cat). I'm in California so swapping the cat is a total minefield, especially with my location therein, but I would love to do a progressive crackles tune. Does anyone know where stock cat + aftermarket cat back falls vs. the above from their site?