If you purchased a high end A/V receiver, I'm sure you would have to get into a much more pricey 2 channel system to hear an improvement. In fact, I'm willing to bet that other components in your system would provide the weaker link before the high end receiver (unless you have ultra high end speakers, transports, etc)
AV Receiver good enough for high end audio?
Have any of you found a modern AV receiver whose sound quality is so good that you are satisfied using it as your high end audio system? Did you toss aside your tube amp and just equip the front of your HT with a finer pair of speakers, a high end DAC, and done?