Filly, nobody knows that they'll sound even better with a "higher end receiver". If your present 2000ES is in good condition it's amplifying transparently with flat frequency response and inaudibly low noise and distortion. Paying more money can't improve on this and "higher end" will essentially mean only higher cost. Yes, either of the receivers that you've mentioned are excellent, but unless you have some specific reason for getting a replacement besides hope, there should be more significant uses of your resources available.
