The PSB Imagine T2 is phenomenal. I love that speaker. Very neutral and flat response assuming it is tuned in well in your room. I have listened to it driven by a PrimaLuna Dialogue Premium HP. For me it sounds a little rolled off but I tend to like tube amps paired with more forward speakers. Due to the fact that this speaker is quite neutral, with a tube amp it will sound decidedly warm but then again you probably know that and I assume is your preference.

The PSB is fairly sensitive at 90dB in that they will get loud with relatively little power but are quite taxing on an amp as the minimum impedance is 2.4 ohms with most of the midrange at or below 4 ohms. That being said, both of those amps are well suited to driving tougher loads and I would set the impedance at 4 ohms.

Assuming your room is small to medium size, technically there is nothing that would suggest that either of these amps would have an issue driving those speakers to reference levels. With 11w of power, volume should be 93.7dB at a listing position that is 10' from the speaker. I personally like those PSBs with a solid state Class A amp but that is obviously to my taste and that POV is worth exactly what you paid for it.

I can't say I have personally heard the Leben but now I want to. Looks like an incredible amp. Good luck with whatever you choose.

I think that you would be a bit limited dynamically with that amp, but it is hard to say because the room and other factors come into play,

It might work fine.

I would suggest that you consider the Musical Fidelity M2si, which is an excellent amplifier with great sound quality and a lot more power (and only $999).

The Pass Labs INT-60 is a mind bogglingly good integrated amp and based on your other amp selections might be the perfect amp. It will easily drive those PSBs to reference levels and would be an A+ selection IMO. If it fits your budget, I wouldn't hesitate.

Another interesting option for a bit less money is the Ayre AX-7e. At $4K it has a lot to like. I have heard Ayre equipment driving those exact speakers (not the Ax-7e) and it was one of the best sounding systems I have ever heard for the money.

I can think of three interesting products in that are definitely in that price range.

Manley Stingray II which is like $5900 and is a tube unit. The Simaudio Moon 340i which I think is like $5800 and the Esoteric F-07 which is a bit more at $7500. I think McIntosh may also have something but I am drawing a blank. I kind of feel McIntosh isn't the best value. The other 3 are great products from great companies though I wouldn't say any of them are better than the Pass you are looking at.

You might also look in the used maker for a Mark Levinson No 585 or an Ayre Ax-5. You might find either in that rough price range and both are obscenely good integrated amps though in both cases, new are like $12K. They might be better than the Pass unit depending on your taste in sound profile but that will strictly be a matter of opinion. The only thing that is clear is that they will deliver more power and will have a better grip on the drivers which should give more refined bass but that is ultimately what any first rate, high power solid state amp should do.

The Pass Labs INT60 is awesome and will be your first choice if you can find a good deal on it. I would second Bierfeldt's suggestion on Mark Levinson if you can find a used one or a great price for it. The Primaluna Dialogue Premium HP would be a good choice as well if you don't play loud. I think it would probably sufficient if you don't have a large room and play your music at somewhat moderate levels.

I would want to add to your list of integrated amp the following :
* Audio Research VSI75 tube integrated amp. This retails for $8500 new. If you can find a used one or a good price for it I would suggest that you give it a listen on your speakers in your own room before buying.
* Classe Sigma 2200i stereo integrated amp. This unit will digitize any analog inputs. It is a direct digital amp. No DAC, the signal remains in digital domain all the way through the amplifier output buffer where it will be converted to analog for speakers to use. Its amplifier circuitry is class D but Classe uses its own proprietry class D design circuitry and is a really good one.
But if you have a turntable or if you have to use the integrated amp's analog input then this unit will not be a good choice. It retails for $5500. Sounded really good. I don't know how it will sound on your PSB speakers.
I heard this amp on B&W 804 D3 speakers last year and tbey sounded phenomenal together.