Best Tube Amp For Sonus Faber? Or Pass XA-100.5? $6-7,500 Budget, Purchasing Used.

As the title says, I have a pair of Sonus Faber Olympica III's that I am more than pleased with, for which I am trying to determine the best available amplifier, preferably tube. Of course, there are always budget limitations and my budget for this amp would be $6-7,500, and I would be buying used to maximize purchasing power.

Based on a lot of research, and quite a few auditions at brick and mortar stores, various home systems, Axpona, etc. I'm honestly not sure if there are any truly exceptional tube amplifiers available within that budget that meet my needs. These speakers need 100wpc tubed, or 200 wpc solid state, into 4 ohms to really open up and perform. 

If, in the end, there are no really great tubed options, I've always heard that the Pass Labs XA-100.5's were probably the optimal choice in solid state for former tube lovers. I would also appreciate any thoughts on that option from owners.