Best high current high power $5k amp for MBL 121


I've narrowed down my choice of amp(s) to the following to help me drive my MBL 121. The speakers are very inefficient at 82db and with a 4ohm load. I can consider amps for around $5k used but would like to spend a lot less if I can. Amps include:

Spectron Musician III SE Mkii
Plinius SA 250mkiv or 301
Pass Labs 250.5 or 350.5
Cary 500MB
McCormack DNA 500
Bryston 7BSST

I welcome any suggestions, especially from folks familiar with driving these speakers, and also welcome thoughts other amplifier options.

I play a wide range of music and varying volume. I'm typically a tube guy, and I value liquidity, airiness and naturalness above all else. I find I care little for pursuit of a low noise floor at the expense of other aspects of music reproduction. I find I don't particularly mind a sound that some may find colored if it breathes life to the music (I have a Supratek Syrah preamp that I love). I've had one or two highly regarded amps that may be considered accurate or transparenet, but which I found to be dead and lifeless.

Anyways, I welcome advice and input on what is an expensive purchase for me that I want to get right. I may also consider a far cheaper amp (a giant-killer, if there is one) that may not get me all the way there, but which will make do for a year or so as a good bridge to a better amp later on.

Finally, might there be a tube amp option for me? Again, I need a high power solution, and even moreso, I need a high current solution - to drive these speakers properly.

Thanks!
128x128outlier
Hi Guys:
Thanks again for the input. I used to own the older model Nuforce 9.02 monos, and I sold them within a week of receiving them, as they were comfortably bettered by the KR amps I had at the time - very different amps, and I was using them with a previous set of speakers - Focal Diva Utopia Be. I'm sure the new/latest Nuforce are much better. I have a good friend who has the Nuforce 9 V2 SE amps and he may bring them by for a listen with my MBLs some time soon.

Another option I may consider is getting the Musical Fidelity Superchargers - that would give me the flexibility to use a lower power tube amp, while still delivering a lot of current, power and headroom for my MBLs. Still pricey though, and so perhaps the best bet is for me to run with the Spectron..I agree Guidocorona about the power issues too - it would be a treat to be able to keep the Spectron on permanently and draw so little power, compared to the more traditional linear solid state designs which can eat power even in standby mode.
High again Outlier, I have the impression that switching amps like NuForce, JRDG, Spectron, and likely many other class D amps take a very long time to break in and reach optimum performance. . . probably about 1,000 hours of making actual music. Make sure that any class D amp you audition has been fully broken in, before you do any critical listening. And even when they are well past breakin, they may require a few days of music making if they have remained turned off / disconnected for a significant spell. Patience is #1 with class D amplification. G.
Just to update - I pulled the trigger on a Spectron. It's just the regular Musician III, but I intend to pursue an upgrade to full SE mkii at some point in the future. I haven't received it yet, but should have it in a week or so. Can't wait to power up my little MBLs.