Solid state pre + power for Sonus Faber Guarneris?

I think X250.5 would be a good match for these speakers.
Also Krell is a good match with SF speakers.
McIntosh MC501 monobolocks would be nice too.

I suggest you go for a tube preamp though.

If you get a chance, listen to a Linn Klimax Kontrol preamp combined with the Klimax Twin amp. Linn mates very nicely with SF.

I am using an original choke supply Jeff Rowland Model 8 and a CAT preamp with my G's. The combo is a great match IMHO.
The G's need plent of stick upline.

I will second newmanoc there seems to be a very special synagi with linn and sonus faber

The linns are very very muical but at littel colourless and thin/bright the sonus fabers are very musical but very smooth full and warm combinened it may very well be ultimat musicality and joyfullness. .

But the klimax gear MUST be pared with highend source off same caliber as the klimaxes or it may have a completly different outcome.

just my 2 cents

"But the klimax gear MUST be pared with highend source of same caliber as the klimaxes or it may have a completly different outcome."

Oh, how true. Without a quality source, a Klimax Kontrol preamp in particular can be your worst enemy. It is simply far too revealing of deficiencies upstream. But with a good source, say even an Ikemi, you have a ticket to audio nirvana. Especially with your Guarneri's.

I don't agree that Linn stuff is bright, but a little thin is a fair description. The gear gives you wonderful detail, refinement, and coherent musical expression, but the sound is definitely not fat. Not gear for the valve crowd.

ARC LS15 + ARC 100.2 You may try