Prior to changing them out, try this........
With stereo OFF, disconnect rcas from amp running components. Turn stereo on, and see if noise is still there. If it IS, its coming from the amp (ground issue) and not the cables. If its NOT, likely your cables are the culprit.
Turn stereo back OFF, and reconnect rca cables at amp, and disconnect at Radio. Turn back on. Noise? if so, its your cables for sure. if not, your getting noise at your radio (change that ground)
Basically, what were doing here is working our way up the chain, and isolating each individual component one at a time. Its the best way I know of to determine where noise is being introduced into the system.

Thanks!!
I'll give everything you said a shot and I'll keep you posted