Pass labs for Sasha's

They are both Mosfet Stan, this is what the Stereophile bench tests say about XA160 which is also Mosfet.

"The actual output power at clipping 118W into 8 ohms, 59W into 4 ohms, and 29W into 2 ohms.
Combinations of low-impedance speakers and large rooms should be avoided with the XA160."

As you can see, no doubling at all down to 2ohm. And this is what your speakers demand to sound their best.

Cheers George

Hi Stan.
From 70hz to 250hz the Sasha's have a very heavy current demand on an amp, they are 2ohm and have a -45 degree phase angle at 70hz.

So an amp has to maintain god current delivery to get the "very best out of them", this means amps that can "almost" keep doubling their wattage for each halving of impedance load 8ohms down 4ohms down to 2ohms. They are efficient at 91db so the amp can be a 50watter into 8ohms, so long as it keeps doubling down to 2ohms.
Like the old ML2 monoblocks they were only 25watts but I bet they would of sounded magnificent on these Sasha's

EG:
8ohms---- 150watts
4ohms---- 300watts
2ohms---- 600watts

These types of amps will extract the very best from the Sasha's. This type of amps will be BJT (bi-polar) output stages, as no Mosfets will do the doubling act like a BJT amps can, and definitely no tube amp can.

Cheers George