For a run that short a 14ga should be perfectly fine. I use 10awg all around just because i bought one big long length of it. I didn't see the point in having 14ga for my main runs, 12ga for medium length runs and then 10ga for really long runs, etc., so i just chose one gauge period.
As for the silver cable/interconnects, i've read many different things but ulitmately it will conduct an electrical signal which is the whole point. Considering it is a different metal it may have a different sound than copper but who's to really say?
It will cost more that's for sure.
I have yet to try listening to anything silver myself.
It definitely won't oxidize as easily as the copper which is good if you are going to bare wire your speakers.
