Pondering a Speaker Upgrade

I have had my new integrated amp Lyngdorf 3400 for almost 3 months now and I'm enjoying it thoroughly.  This is my first venture into high end audio with my previous set up being a Marantz AVR with Rotel 1582 power amp.  I am running the Lyngdorf with Martin Logan Motion 40 tower speakers.  Most on this site would consider these budget speakers  but in my view they sound pretty good.  Lots of detail with the Lyngdorf but still pleasing to listen to.  Good soundstage and imaging is fantastic.  I am using with a Sub which the Lyngdorf integrates perfectly for a bottom end that is really sweet.  The Room Perfect correction (a must in my space) is excellent.  However I have always wanted a complete high end system and I'm wondering how much better premium speakers would be with the Lyngdorf. I have been eyeing Bowers 805 d3 thinking standmounts might be better in my somewhat small listening space especially with a Sub.  I went to hear the 805s at Magnolia and though they get a lot of praise I was totally unimpressed.  To my disappointment they were driving the speakers with the same Rotel 1582 amp I upgraded from.  Not only did they not sound great the setup sounded small and in no way came close to the Logans driven by the Lyngdorf even with the Sub turned off.  I also greatly admire the Sonus Faber Olympica line of speakers but they have no dealers in the Washington DC metro area.  So my question is how much improvement might I expect in my system upgrading to a speaker like the 805 d, 804 d or Sonus Faber Olympica I or II  or similarly priced speakers. The Kef Reference I had also peaked my interest.   Especially if I'm using the sub could I expect an overall improvement in sound quality in the 30% range or would the difference be more marginal?  I know that different speakers will have different sound qualities but wondering in general if I want to consider an upgrade.  What I liked about the Logans when I bought them were the highs and mids.  They sounded much more alive and forward than Bowers and the Faber Venere similar in price.  While I still like the Logans I think my taste is changing and I would maybe choose something a little more laid back but not too laid back.