Congradulations.
Sounds to me as if you are endorsing high end cables… not specifically XLR. For the most part my experience has been that what usually counts is the quality of the interconnect more than whether they are single ended vs XLR. I recognize there are exceptions to this generality… in both directions.
@audphile1 +1
Yes, I also recommend trying a power cord… specifically for your amp… one designed for an amp. Some folks experience an even bigger difference with the power cord versus interconnect.