Von Schweikert VR-4.5 amp recommendations?

I'm currently using a DJH AE-3 preamp with a VTL ST-85 amp, bi-wired to the VS spkrs. Looking for more speed and cleaner bass and mid-bass. VTL amp in this set-up is a little too loose. Thinking about going solid state, maybe McCormack, Mark Levinson, Threshold S300, Ayre V-3, Spectron Musician II, CIA, Classe, Nak PA5. Even though these speakers have good efficiency they seem to require a lot of power to come alive. I would guess high damping to be a priority. My price range is up to $1,800 max, but would prefer staying around $1,500. Used is ok. What have you tried or heard?
In that price range I have been extremely happy with Bel Canto M-300s for my VR-4JRs. Or the IA version S-300. Plenty of power, clean deep bass, smooth highs. Sometimes available used. I bought mine from A-gon seller Walter at Underwood Hi Fi and have always been very pleased with his service (no affiliation).
I have the VR4.5's and have only tried a few amps - namely Simaudio W5, Parasound JC-1 and Aragon Palladium 1K. Surprisingly, I preferred the W5's by a VERY small margin. As for bass/midbass speed and clarity - all these amps had it in spades! You would think those monster monoblocks would stomp the W5, but no. The W5 just seemed a little less colored in it's sound. I think some people might call the W5 a touch dry sounding, I call it accurate and clean.
Also surprsingly, I preferred the 1K to the JC-1. The JC-1 seemed a little more harsh sounding in the mid/upper registers.
I've tried very few amps in my home because, quite frankly, I have been very satisfied with the sound.

All you choices are very strong. The only one I might give some pause to is the Mark Levinson. I thought about getting one a number of times but the reviews of their "dry" sound scared me off for the 4.5's.

Years ago, I did have a McCormack DNA-1 Deluxe in a different system and that amp was really nice sounding too. Unfortunately, and apparently NOT typical, I had reliability issues and subsequently sold it. Unfortunately, their newer offerings are a little pricey or else I might try them again...
I went through this same situation about three months ago. I called and spoke with Albert Von Schweikert and he recommended a tube integrated to me. I came from a class A SS amp and thought I wanted to stay with SS. I could not be more satisfied. This is my first tube amp, although I have had several tube preamps. By the way, Albert told me he voiced the VR4.5 with Spectron Musician amps. Good luck.

Jerry -- just to put us out of our misery, what WAS that tube integrated you ended up with :)
It was an Audio Space Ref. 3 using the KT88 tubes. Albert is selling these in his showroom and he upgraded the caps in mine as he suggested. Albert says these amps have a special synergy with his speakers. At first I felt I had given up some bass, but gained quite alot in detail and soundstage, but after the amp settled in at about 100 hours, all of my bass is back. The only thing I feel I have given up is police calling volume. The qualities gained far outweigh this. YMMV.
Thanks -- this sounds like the same manufacturer that TAS mentioned as sounding particularly fine with the VR5s recently in a show review. Pity there are so few dealers!