I demo'd a 35wpc Primaluna on my old Salk Songtowers. These have the same 88db efficiency as the Song 3 but at a tougher 6ohm impedance with a dip down to 3ohms. No problem...nice and loud...plenty of bass slam. And they sounded better on the 8ohm taps!
The Song 3 BeAT are an easier 8ohm load. All Salk speakers are relatively easy to drive with most modest/high quality power amps.
A good 30+w tube with a decent power supply will be fine.