Is it upgrade from SF auditor to Harbeth SHL5 plus?

There is not much of a class difference going from what you have to a Harbeth. 

if you want to get more extension look for a suitable floor stander and one with more advanced driver technology. 

It will come down to budget and room size and matching gear. 

We just had a client trade in a pair of Sonus Faber Cremonas to the new Paradigm Persona 3F as he also wanted greater  clarity, and he is very happy.

Dave and Troy
Audio Doctor

chayro, thank you very much! Home audition is not possible. I will take your advice to keep auditor and do A/B test in my room. 

I am familiar with both speakers, which, IMO are both excellent.  The SHL 5s do have a "bigger" sound IMO, but unfortunately, without a home demo, there is no way to predict which one will sound better in your listening room.  In the right room, the SHL5s can have a huge expansive sound, but choked in other rooms.  My advice is to see what you can do about getting a home demo if possible.  If buying used, I would not sell the SF until I had a chance to A/B both in the actual room they will be used.  You can always turn Harbeths over without much of a loss when you buy used.  I really love the SHL5 and I hope they work out for you.