This quote below is from Transparent's website vis a vis their RCA Reference cables. My old interconnects were first generation Transparent Super, two levels below Reference, so I expected a significant performance impact, and, didn't get it.
"REFERENCE RCA Interconnect is a significant performance upgrade compared to ULTRA RCA Interconnect. Reference level cables are the first products in the Transparent family to be custom calibrated for the specific electrical output characteristics of your components."