I use a Classe CP-65 pre with a B&K amp on my Cremonas and have also heard them with Mark Levinson and Edge separates. I particular like the Edge and Classe electronics with the Cremonas.
For integrated amps I auditioned Cremona's with Primare and with the Pathos Classic One. The Pathos was much richer sounding, with more detail. The cables were mid-range Nordost, but I do not remember which ones. I would skip the Primare.
I heard the Cary SLI-80 with SF Grand Pianos (home, not current Domus) and it did not really bring the Grand Pianos to life - not enough detail and the Sonus Faber musical sound did not just come through. It may do differently with Cremonas.
There is definitely a Primare-Sonus connection in the US as there are both distributed by Sumiko. Not sure that translates back to Primare and Sonus working on development together, however.