I can't believe that you can spend $20 grand on a home reciever. At that price it better wash my car fix breakfast and take me to work.When I started upgrading my university days crappy stereo equipment I was going to buy a "highly rated" but in truth a mid-FY receiver. The stereo shop had one in stock and the price was agreed. Then the sales guy said "before we write this up why not listen to this". And he demonstrated a (20 Watt) NAD 3020 integrated amp. The improvement in sound quality was unbelievable. You just can't buy mid-FY stuff when high-FY (or at least borderline high-FY) stuff is readily available and not even very expensive.
So my suggestion is pick one really good component that works with the stuff you already have and add good stuff to your system over time. That's how you build a killer system without spending big bucks.
You don't have to go crazy and buy a $20,000 preamp either (I made that price up but you get the point). My not so expensive Mirage M1 speakers were rated as "the best in the world" by "Absolute Sound" magazine when the second best speakers were 10 or 20 times more expensive. [For the record the Mirage M1 speakers were developed by stereo gear heads using the National Research Council's anechoic lab in Ottawa.]
And working high quality vintage stuff is fine too. My Mark Levinson Power Amp was a few years old. The old stuff can even be fixed.