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

Save yourself some money by going on a different path: less known brands that are offering amazing products for fair prices. Most of them are class D, like Class D Audio, Ghent audio and Temple Audio (I just bought the monoblocks from Temple Audio, soon will post a review).
Or the small, cheap and extremely fantastic KingKo Audio, a tube integrated amplifier that is also a headphone amplifier.
If you want to go boldly I can sell you my Line Magnetic 219ia for much less than 6k. And this is a musical beast! Just check all the reviews. (just too big and heavy for my back and my room, that’s why I go smaller from now on).

whatever you choose, when considering costs, don't forget resale value...the Pass X250.8 bought used will probably not lose much, if any value over the next 2-3 years, while homemade, or lesser known amps may lose much more, and cost you more in the long run...just assuming you won't keep whatever amp you buy forever...

I know this thread is old and you bought the McIntosh MC 501Mono blocks I wonder if you are satisfied with the 501Mono blocks?  I have owned mine for 15 years back then I was driving B&W 802N Speakers and before I bought the Mac's I owned a Krell 600c ,I've been very happy with the McIntosh 501Mono blocks they still sound fantastic! Now I have Sonus Faber Amati Homage speakers with ModWright LS 36.5DM Tubed Linestage a killer combination, it's funny I called McIntosh about replacing the caps the rep told me wait about 15 more years! I asked him about the new 611 he said hang on to the 501Mono blocks there way under rated. Happy listening my friend! 

Well, 3 years later i purchased a pair of Brand New McIntosh MC501's, store demo C2500, NAIM NDX 2/XPS DR (Streaming), and still have my BOSE 901 VI. The speakers are the weakest part of my system, so maybe B&W 800D vs 800D2? What's your thoughts?