Best integrated up to $6000

A used VAC Sigma 160i or the previously suggested VAC Avatar.

Though it depends on your speakers and room size too. If your speakers/room are up to it, an Allnic T1500 could work out very nicely too.

He's right. I really shouldn't have made that recommendation without more info on you room and system. It's a great amp, but it may not be the right amp for you.

Yes definitely depends on your speaker choice, room etc but the LFD NCSE is worthy of consideration in this price range. It's a sweet piece and one I have not considered changing since I received it.

Jeff Rowland Concentra 2. If you want to go tubes the McIntosh MA2275. You could build a near SOTA system around these amps!

Hi Erasto,
As already pointed out it depends on what your speakers are. If you have relatively efficient speakers(and easy load characteristics) I'd strongly consider the Coincident 845 Turbo amplifier. For more information there's a current review on 6 Moons.com. A 845 SET amplifier is terrific for your musical taste. The sound is exceptionally natural and realistic. The direction is music reproduction more so than hifi emphasis.
Good Luck,