I would think the 5 would be up to the task as I had a 4B ST & replaced it with a 5. I had more efficient speakers than you do but on a comparative level the 5 did everything the 4B ST did in terms of adequate volume but much more musical. I sold the 4B ST as it was too analytical for me & subsequently sold the 5 as it wasn't quite what I was looking for. I now have an Ayre V-3 which I'm really happy with but will probably move up to a V-1.
I would say if classical, jazz & female vocals make up the bulk of your listening, then the 5 will do it for you. If you prefer rock, electronica, metal & so on it may not float your boat. That was my experience with the two amps.
Of course, the best thing would be to try an in home audition but even if you purchased & it didn't work out, you'd be able to resell easily. Good luck!
I would say if classical, jazz & female vocals make up the bulk of your listening, then the 5 will do it for you. If you prefer rock, electronica, metal & so on it may not float your boat. That was my experience with the two amps.
Of course, the best thing would be to try an in home audition but even if you purchased & it didn't work out, you'd be able to resell easily. Good luck!