High power amp reccomendations, airy highs a must

One of the Musical Fidelity big integrated. They weigh about 110 pounds [separate power supply] and put out more power than you are likely to need. I have the smallest one , the NuVista M3, which is 275 into 8 about 500 into 4 and close to 900 into 2 with one channel driven. The 500 is , of course 500 into 8 and the 550 , well, you know. The TriVista is between the M3 and the 500. The bad news is they have 4 tubes in the front end, the good news is that they are very small and cheap and last 100,000 hours. Or 20 years of time left on. They have excellent highs and VERY tight bass but not the brightness you are talking about. I also cannot stand this. I have been a confirmed SS user since 1964 so don't worry about these having a "Tubey" sound. These will run from around $2100 to $5000 depending on model and condition, I don't know of anything else with the performance for the money. Also very well built.

McCormack DNA-500

I like the coda and mccormack recommendations so I will add
Belles and Odyssey into the mix;what speakers are you going to be driving with the new amp?

A couple of questions:
What is your budget?
What speakers will you drive, with what sensitivity?
Will you be running single ended or balanced?
What is your pre, with what output impedance?
What wiring do you use?
What music do you enjoy listening to?

Regards, G.

To answer a few questions ... I'm driving PSB Stratus Silver i speakers via Goertz MI2 bi wire speaker cables. Pre-pro is a Reference B&K, front end is a Lexicon RT-20 with 7 nines solid silver interconnects.
I consider my system pretty much neutral to my ears with very few minor sins, if any. Only thing I'd like to see improved is a little air in the highs and a little more taut and controlled bass/mid-bass. This has been well documented to be the hallmark of the Stratus speakers, but changing them is not an option, as I have heard NO speaker that can play as loud, sound as real on drums and stay musical at any level .... at least that I can afford. I'm fairly sure a change to a more resolving power amp with a high level of bass control and airy, extended highs will get me that last little bit. Problem is: My budget maxes out at $2000. Used will probably be a must.
I've also considered replacing the tweeters with a world class tweeter from Scan, but have NO IDEA how it would mate with the rest of my speakers in the cabinets.