I'd second Imin2u's statement. I have B&W 602 S3 speakers (last year's large standmounts) and have found different speaker cables - even switching from copper to silver - made little discernable difference.
I like my 602's, but I believe the 600 series B&W's are simply not resolving enough to warrant large expenditure on cabling; don't buy anything you can't return or sell!
I like my 602's, but I believe the 600 series B&W's are simply not resolving enough to warrant large expenditure on cabling; don't buy anything you can't return or sell!