What 2 channel Amp would you Buy for $6k?

Can’t go wrong with Ayre or Jeff Rowland 

That's probably true, but let me ask you something. What do you think about Mcintosh products compared to Are and Rowland?

If you can have anything, I'd definitely opt for  Classe DR3 VHC. They only made around 180 of them and they're hard to find, but usually go for c. $3K unserviced and $5K serviced.

They will run absolutely any speaker ever made, including 1 ohm speaker killers like the Apogee Scintilla with 1 ohm impedance.  Only 45 watts but they are Class A watts and if you need more power, buy two and bridge them.

The only other amp I'd go for are almost impossible to find - Levinson ML-2.

Nobody can recommend an amp by itself without knowing your sonic preferences and the rest of your chain from source to speakers. Ignore any and all advice from those who do. And, if you want good advice, then provide this info.

ljgm is exactly right. 
We are living in a golden age of hi-fi and there are ... what? 20 amps? 30 amps? that would suit your needs.  All info would be good, but to fine-tune the options at an absolute minimum you should include your speakers.  In fact the amp/speaker combination can be seen as a single unit ... active speakers anyone. 
(I am running Pass Xxxx.8 at the moment.  If you can live with its downsides of the .8 - weight, heat, warm-up time then it will drive almost any speakers in almost any room.)

I agree with the McIntosh MC-452 comment above.  I spent the same amount for a mint condition six month old unit and haven't looked back since.  Imaging increased significantly from my previous amp (MC-301).  Go for it.