hey guys ive got headers and a hi flow cat, 2.25" single system with a resonator and a straight through sports muffler ( fiber filler perferatored mesh) on for a while now and between 3500rpm and 4500rpm it sounds raspy and fluttery. i drove it for a while and its now anoying me.

so i went back and the exhuast shop and they swapped it over to a glass filled muffler and a different brand, but its made it even worste.

does exhuast raspyness/ rice sound come from the resonators or the muffler?

any info would be helpfull so i can pass it on to my exahust shop so we can sort it out.