cam regrind?

I want to get a better sound out of my sc. It has full dual 2 1/4" exhaust with flowmasters and hi flow cats with no resonator. It sounds nice untill you hammer it, then it sounds rattly. Would running dual resonators help? I also want a deep, lumpy idle and was wondering what the best cam to run is. I want to keep the stock valvetrain and timing chain. Any help would be appreciated


Thanks