impedance vs sensitivity

I know the VSA VR-6s that I owned were 96 db with impedance dipping down to 2-3 ohms (on the woofers).

50W SS or tube? SS might work,tubes would be pushed too hard to develop power into that load.
My Air Tight ATM 3s drove the top-end of the VSAs,but were not enough to sufficeintly drive/control the woofers (same with Audio Physics Virgos).You could switch them into "ultra-linear",but the magic was gone.