The minimum impedance is important but I like I stated earlier 3 ohm is really not that low.
Now to me, SS power seems to have more guts to handle those issues. Tubes can be iffy. Although, I love the sound of tube amps. I am using Bob Carver Raven 350 mono block amps. They are rated for 350 wpc but I really don't know how many watts I am actually using, far less I'm sure. You can never have too much power, especially for dynamic swings and deep bass.
If the Sopra 2's are nearby, perhaps you can take your amp to the audition?
ozzy.