Which components are "stupid good"?


Which components, known to be outstanding in their category, have a performance to price differential such that they can truly be called "stupid good?"
pmboyd
Speaking of the Linkwitz speaker, there is a related product that is uniquely good---the GR Research/Rythmik OB/Dipole Subwoofer. The bass in the Linkwitz is produced by a similar design---two 12" woofers facing in opposite directions and wired in opposite polarity. You may remember an also similar product from the 1980's, the Gradient sub made specifically for the QUAD ESL63. But the Rythmik A370 plate amp contains the patented Direct Servo Feedback circuitry that, in conjunction with the co-designed woofers, produces the cleanest, tightest, most articulate bass you have ever heard. The sub is available only as a DIY kit, which contains the two woofers and amp. Plans for both a W-frame and H-frame into which the woofers are mounted are available on the GR Research website. The OB/Dipole sub produces bass voted "Best Bass At The Show" at multiple RMAF's. 
I went to Best Buy to check out the new B&W D3 804 speakers . They sounded  very nice  "BEST" on the floor , I did listen to there other brands , Sonus Faber , M.L., few other brands put the D 3 804 on last was not even close .I could only find one thing wrong with these speakers ,
the price !!! I almost fainted  lucky for them I had a empty stomach .So down payment on a new car or walk to work ??? and it was 2 below 0 outside not to mention dangerous drivers . The 804 speakers gave off little heat , So I went with car. ""BUT"" when the salesman showed me he was running them thew the new Rotel RA-12 amp using the built in dac as a source . I bought the amp , Its very good well made w/lots of options and turn table hook up. Clean and well define . The price is reasonable , I just have butter a few more million bagels to make the $$$ to pick up the speakers . Best Buy gives options on a no interest loan plus no Bull Shit fees . And you can bring anything back if you don"t like the product , No any dealers do that ???
I had mentioned Magnepan MMGs and I still keep them on my list... but I add
The Parasound A21 power amp and
The Bluesound Node 2
The Node 2 can Stream music to multiple Bluesound Players all over the home.
It can access and connect to internet radio stations like Pandora, Spotify, Tidal or Roon so it is a Hi-Fi streaming device.
It can access cloud music services and your own local music library.
It will unfold and Play MQA files (which sound spectacular)
It controls music wirelessly with an intuitive Controller App for iOS, Android, Kindle Fire, and Windows & Mac OS X desktops or mobile device like an Ipad, Iphone or Anroid phone or tablet.
Simple to setup, easy to expand. It also has a great DAC!