Help an old man out

i agree with the earlier suggestion of a hegel - h190 or 390 would work well for your power needs

simple elegant styling, excellent sound, plenty of power, very nice remote

JRW,  thanks for the post...agree with you 100%.  The S300 could drive the Gallos okay, but I wanted that headroom and control and the only way to go is up.  
How is soundstage comparatively between your M33 and your Prima Luna?  The reviews I have seen that focus more on the sound of the 33 have said the new Purifis make a huge difference in sound...big improvements over the n-cores etc. when it comes to tighter bass and even lighter highs, which my s300 def lacks.

WAF...that is awesome lol.  Mine is actually very understanding.  She is the one who told me to get the M33, but she is pretty supportive of my hobbies, even when they get expensive.  I showed her the Sonus Faber Serafinos that are on auction right now and she loves them...still waiting for her to tell me to get those!

Headphone dreams/JJS, following your posts I went back and relooked the 390...it is definitely a consideration. Looks quality!

+1 jrw1971 re your point about impedance not being a crock.

Aside from his stating the importance of speaker sensitivity Robert Harley states  " Another electrical factor to consider is the loudspeaker's load impedance. ....The lower the loudspeaker's impedance, the more demand is placed on the power amp. If you choose low impedance speakers, be certain the power amp can drive them adequately."

OP -- as between the PL and the M33, my impressions (all the usual caveats):  

M33 has more grip and authority, no question.  More dynamics.  Jump factor.  But sometimes I felt that the bass and lower midrange sounded artificial, as if I had improperly integrated a small, crisp sounding sub.  Or like comparing a drum machine to actual drums.

I've been on a kick recently of hyper-focusing on attack/sustain/decay.  Decay is tricky; too abbreviated sounds nice and crisp and enunciated, but artificially so.  Too much decay eliding into the next note gets sloppy and blurred.  The M33, I think, abbreviates the decay a smidge.  I think the PL gets it right.  But perhaps with some attack edges that are a smidge, well, edgy.  More on this below.

You asked about soundstaging.  To my ears, a clear win for the PL.  More dimensionality.  The way I see it is you have a few scenarios: (i) 2D in a 2D space.  Cardboard cut-out 2D.  Yuck.  (ii) 2D in a 3D space.  Cardboard cut-out players, in a 3D space, giving you some depth and width and layering.  But each player lacks realistic shape; within that 3D space each player is 2D.  That's where I put the M33.  (iii) Then you have 3D in 3D, which is where I put the PL. 

My issue with the PL is glare and bite.  Too much of both, by a smidge.  Countless times over the last 5 years, I will pop it into a system, and think "wow, better than I remember; this thing's fantastic."  After a few weeks, that smidge of glare, edge, maybe a dash of grain, starts to become noticeable.  Countless experiences like this.  

The M33, perhaps mindful of the sins of Class D's past, doesn't do this.  It sounds good.  I like it.  I still use it in my third system.  But it doesn't quite achieve realistic imaging, air, shape, and palpability.  But, to be fair, it now lives in a room, and with stablemates, that don't exactly invite those characteristics.

Last point, I have noticed over several different speakers that the PL can sound a bit boring with particular speakers.  My previous Vandersteen Treo CTs did NOT like it.  NOLA KOs loved it.  Harbeths, somewhere between love and hate.  Wilson Sabrinas sounded awfully good on the PL, even with their not-so-easy impedance dip, but that was a 3-5 day experiment.  Just from a quick google search, I'm getting a hunch that the Gallos want more than the PL will give.

To state the obvious, while a $5k amp gets you sound that's approx 8000 times better than a barebones Sonos system, and forever enjoyable, it will not give you the sound of a $30,000 amp.  Cursed hobby.  In my own case, all I can say is to avoid listening to well set-up, well-matched, uber high end systems.  Hard to recover from those experiences and stay in love with your current gear.  Anyone who says you can get 99.9% of the million dollar sound for under $10k, hasn't heard million dollar sound in a good room.  Long way of saying that I've become a hard grader, and it's something that plagues me with my own gear.  Like you, I don't have unlimited funds, and I also have a wife who knows what "spousal parity" means, because she's smarter than I am.