Need options on fixing a raspy exhaust

[Rx8Bosnian]

I bought a turboxs full catback and high flow cat about 3-4 months ago. now its obnoxiously raspy, but you can still hear the rasp around 4k rpm when the powerband starts kicking in. now i was thinking about getting a inline resonator and wielding it on and i just wanted to know if that would help out with the rasp. Let me know your opinions.