KCAG has the same wire in both balanced/XLR and unbalanced/RCA versions---all three legs of silver in both versions. Balanced/XLR and unbalanced/RCA Silver Streak, on the other hand, are different from each other. Balanced/XLR Silver Streak has two legs of silver, one (ground) of copper. Unbalanced/RCA Silver Streak has only one leg of silver, the other two of copper.
So in Balanced/XLR form, Silver Streak is different from KCAG only in having copper for ground as opposed to silver. Does the copper ground wire of the balanced/XLR Silver Streak result in it being sonically inferior to the all-silver KCAG?