a high flow cat is expensive, but it sounds good. without the cat will be slightly louder and has the possibility of rasp, even with the resonator still there. so here are your real choices:
cheap - just mufflers - will be the quietest and least possibility of drone/rasp
not as cheap - mufflers and straight pipe the cat area - will be the loudest and might rasp/drone
not cheap - high flow cat and mufflers - will sound the best