Mark Levinson 436 Monos vs. Classe CA-401 stereo ?

Since you asked what direction to look in, here is my recommendation:
A friend of mine had the Classe CA-401 as well. He used the Avalon Eidolons as his speakers though. (Eidolons are notoriously difficult to drive well.)
He tried quite a few monoblock amps before settling on his final amps. (He tried the Kora Cosmos, BAT 150s, Manley Neoclassic 250s, VTL MB 450s, Rowland 501s).
His final amp was the Lamm M2.2s. 220 wpc of incredibly clean, musical power. He said he has found his final amps.

The have an extended treble, with lots of decay, but no brightness. They have a deep, quick authorative bass response, without a hint of boominess. (The best bass he has managed to get out of the Eidolons btw!) And the mid-range has just a touch of that tube magic, without being euphonic. Vocals are sensational to say the least.

After I listened to them, I too fell in love with their sound. (However, I could not afford a pair of new Lamm M2.2s, so I found a pair of used M2.1s (200 wpc) to power my Revel Studios.) The sound is incredible, and I too have found my last amp as well. The M2.1s are withing spitting distance of the M2.2s sound, for less than half the price. I "think" the M2.2s have just a touch better treble. Other than that, not really much difference.)

PS My Lamms replaced a Levinson No. 23 amp, which while a very good amp, is not in the same league to be honest. (And rightfully so, as the Lamms cost 3-4 times as much on the used market.) I love the sound of the Levinson amps, since I had a Levinson amp in my system for almost 15 years.

PPS The Lamms had a bit more power than the Levinson as well, even though they are rated the same. (I guess the separate power supplies in the monoblocks added a bit more power!) Don't worry if you think the Lamms don't have enough power for your speakers. Trust me, they do!

I had the Classe CAM 350 Monoblocks on my system for a week. They sounded good in many ways and I was considering purchasing them. Ulimately though, I really wasn't overwhelmed with the slam, authority, and control so I held off. Next up was a Levinson 336 stereo amp which I bought, and I was very satisfying compared to the Classe. Then I had a chance to upgrade to 436 monos. Lookout, they had everything. Better imaging, sense of space and pace, more dynamics and lowend slam (In fact on my Revels they easily outdid the Krell 350? monoblocks that I auditioned at the same time) , I could go on. I have also used many different pieces of equipment with my 436s, and one of the best combos, before I went with the #32, 31.5, 360s was the #39. It has a fine preamp section, and is a close to SOTA CD player (you could update it to a #390s for better sound).
I've not heard the Piega speakers but have heard many good things about them but you're on your way to a fine system. I would also recommend Synergistic Research wire to hook eveything up.
I do have a pair of 436 amps for sale if you want to look at them on Audiogon. http://cls.audiogon.com/cgi-bin/cls.pl?ampstran&1136401085

Thanks for your responses, guys. I actually did buy a CA400. I've been very pleased with it. It was relatively inexpensive and, like the Classe line as a whole, has a great reputation for reliability. The sound? "Pretty darned good," but by no means "the final word in sound reproduction". Kurt Tank: I've heard (read) quite a bit about the Lamms. I'm intrigued, but may have to win a small lottery before getting any of them. I hope some day to hear them. Sgr: Good advice. I've read and re-read your thoughts. Cheers.