I had both Arms, silver wired and copper wired. The silver wire can transport 6% more information based on its structure than copper (AES Standard copper in purest=100, Ag=106).
You hear at once a deeper soundstage, a better headroom and the details are bit more precise and present. that wired Arm is a touch closer to a real thing reproduction. Of course I sold the copper wired Arm :-)
Btw. my FR-66s is also silver wired ....