Zu Soul Supreme with Leben CS300xs (or Harbeth XX.X?)

I am a newbie and this is my first post so apologies if this has been discussed out there on the interweb. I have been building my system over the last few years and have finally found myself a proud owner of a Leben CS300xs. I really love it playing through my Fritz Carrera's, however I do feel like there is something missing at higher levels. I can't describe it, because they certainly can play LOUD, and full, but from reading around here it may be dynamic compression that I'm hearing - things get just a tad muddy and vague. At lower levels, it is a truly a beautiful combination, so warm, yet not syrupy, and very rich. But I do feel like something is missing, which has led me to research more efficient speakers.

So my question: I was wondering if anyone has heard the CS300 with Zu Soul Supremes? I used to have a pair of Soul MkIIs with a Marantz 2015 vintage amp and the sound was really sweet, but veiled, and a bit bloated in the bottom end. I did love the way the Zu's really sucked you in, a strong magnetic energy. Sometimes I wanted a mellower relaxed presentation, and the Zu's had a hard time with that even at lower levels, but they were so fun. I wonder what a step up the Zu chain would be like. I had to sell the Souls when I moved to California, and just recently bought the Fritz Carreras. Nothing against them, they are a beautiful sounding loudspeaker, and Fritz was an amazing guy to chat with and very generous with his knowledge and helping me understand certain audiophile language. But I can't stop thinking that more efficient speakers may really bring my little Leben to life. I've read about the Devore's and I feel they would be somewhere between the Zu's and Fritz's but alas they are probably out of my price range.

Another question - I've read that the Harbeth / Leben combo is really great. But assuming most people are talking about the Leben CS600 because the Harbeths are not that efficient... Just wondering if anyone has heard a CS300 with a pair of Harbeths 30.2's or around there? Opinions?

If anyone has a pair of Soul Supremes in the San Francisco Bay Area and would let me play my Leben through them for a few minutes I'd be so grateful. I will bring gifts!

My source is a PS Audio Directstream Jr. 
I listen to all kinds of music, from Jazz to Hip Hop to Singer Songwriter to Acapella

Thanks y'all!
I have heard the CS300 with Zu Omens.  On acoustic music it was jaw droppingly good, huge sound.  Like you I found with rock the Leben would compress and shout if I tried to play it too loud, like over 80db, so IMO you may be hearing the limits of the amp and not the speakers.  Sean Casey of Zu told me he prefers the CS600 to the CS300 with his 16 ohm models.
Hey Whoopycat thanks for the reply. So both amp and speakers can cause compression.. Ok that is a good piece of knowledge. I rarely go above 80db, and everything is pretty great around 70-75 db. But I occasionally like to play classical music, or big band jazz, and it just starts to sound muddy. I have the dial around 2 o'clock to hit that 80-90 db level. I wonder if I had say the Zu Soul's which are 99 db/w efficiency, if it would sound less compressed, more open, more real. I've also had my eye on the Klipsch Cornwalls, although if I had a pair of speakers arrive on a crate my girlfriend would probably freak out. They are huge!
If you keep it below 80db then I think it would be a fantastic combo.  Between 9-10:00 on the dial was extremely loud with the Zus.
I've owner the 300x and the CS600 both awesome amps. These amps are not that poweful and do run out of steam if the speakers asks for more than they can handle. Better get answer before getting the speakers. I've heard that Zu speakers are very efficient but like big power. Maybe someone with more experience can explain that better. If you are on Facebook there is a Leben forum and a Zu forum, better to ask in those because all 2,000 or however many own the same product. Finding good info in these forums is increasingly difficult.  
Thank you both for the replies. Bjensien, maybe here's a question for you. Did you find a speaker pairing your really loved with your 300x? Maybe that's how I should have started this discussion. I believe the Fritz Carrera's to be an excellent loudspeaker, but I just have this feeling that I have a mismatch pairing with my little Leben. And between the two, I feel like I would like to keep the Leben. 
I have been reading a lot about Devore o/93s. Looks like some have found those match well with the Leben 300's. My budget is hopefully under $5k so just outside of my price range, but never say never. Also the Klipsch Cornwalls although they are HUGE and may not be appropriate for my home. Omega's seem to be thin sounding if I believe the forum chatter. Harbeth - Leben seems like a popular combo, but I think maybe more for the cs600.  
I have not heard the CS300XS with the 0/93’s but have heard it with 0/96’s, a great combination.  I preferred the Leben over the Shindo amp, possibly was the Montille but can’t say for sure.  The Proac D20R was also an awesome match with the Leben.  The bass punch from 15 watts of Leben into the Proac)s was truly remarkable.  I don’t think you could go wrong with either the Devores or the Proac.
Thanks rhljazz for your comment. I have not looked into Proac, thanks for that suggestion, curious about what a ribbon tweeter sounds like. I also wanted to correct one thing from my previous post. The dial on the Leben is at about 10 o’clock to get to the sound pretty loud, around 85 - 90db. I do want to say one thing, I think the Fritz Carerras are an incredible speaker, and in no way am I unhappy with their character. They are so full bodied, relaxed, but still punchy and dynamic. Amazing bass for the size of the speaker, especially with the Leben. Definitely more relaxed than the Zu Soul’s I used to own, and sometimes I do miss the immediacy of the Zu’s, but its a trade off I’m happy to live with. Because to my ears the Carreras do so much right. I have now heard them through a Sugden A21 Signature Integrated, and a vintage Marantz 2015, and I was super impressed, especially listening to what they did with my baby Marantz. They pulled out so much detail from that little amp. Previous to the Carrera’s I had a pair of Fritz Morel 6’s. I loved the 6’s until I heard what the Carreras could do. I’ve actually been meaning to write a review of the Carreras to add to the many already out there. So it may just be the amp is running out of steam, its hard to confirm without testing out different gear, and I just don’t have the resources to do that. I suppose more than wanting to trade out my Fritz’s, I’m more interested in what a full size speaker with higher efficiency might do with the Leben. Forever curious about what else there is out there!
Avgonzalez77 I sold the 300x because my goal was to keep my Nines for a while and try some subs to add weight and maybe keep them for a few years before going to the O/93. The 300 was my intro to Leben and I ended up with 600 for a couple of years. In the end if I ever go high efficiency again I’d consider another 300. I have a friend with the 93/ 300 pairing and he was enjoying it when we last spoke. I appreciated many things about the 93’s but over time I found them not for me. I sold them to a guy that sold his first set and missed them! Everyone is different there are only tastes and opinions.
thanks for the insights Bjesien! I think the 300 may move up to the 600 eventually. I love the idea of trying out the EL34s. I'll be on the look out for a pair of o/93's, they are pricey though, so it may all be wishful thinking. For now the Carrera's are pretty dang nice. Upgrading is addictive, and at some point you just have to realize what you're listening to is better than anything you've heard before and allow yourself to be happy!
avgonzalez that's a wise statement. A friend told me once that what I'm looking for in a system might not exist- there are always tradeoffs.  The 600 has more power but if you don't need the power, I actually prefer the tighter, faster sound of the EL84's in the 300 (to each his own). There is a great comparison of these 2 amps written somewhere and some guys have both because they each excel at expressing a different part of instruments. It's not about the power with the Leben. Good luck in your search!
So I have the Carreras...
Pass x-150.8..REL G-2
XP-20 pre..
Lots of other stuff...
you can crank up the Fritz Carreras....100db..
It’s not the speaker..

Thanks Reruam. Yeah, from what I am gathering here, its most likely just a slight mismatch for higher volumes. But dang, they sound good together. Especially that bass boost at super low levels, it really carries throughout my living space. Makes for a beautiful background sound.