"could you please advise how the DSD upgrade improves the SQ?"
See this report:
http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/ayre%92s-%24500-qb-9-dsd-upgrade-sonic-report-16777/
Also, be warned that the waiting list is said to be quite long. Be prepared to be told you have to wait several months. Regardless, I'm confident you'll find the improvements far out-weigh any possible gains from power cord upgrade . . . and I don't care how much you spend on a cord!
See this report:
http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/ayre%92s-%24500-qb-9-dsd-upgrade-sonic-report-16777/
Also, be warned that the waiting list is said to be quite long. Be prepared to be told you have to wait several months. Regardless, I'm confident you'll find the improvements far out-weigh any possible gains from power cord upgrade . . . and I don't care how much you spend on a cord!