rsure, Thought Id lend a voice for the SF Olympica III's I currently own the OlyII's and love them. I have driven them with lots of differing gear, old and new... The PL gear is wonderful stuff...
My Oly II's sound great with my ARC DS-135 130 watt amp and LS17SE preamp... I do have an ancient M&K 125 sub which I have crossed over at about 35Hz and blends seamlessly driven off the ARC speaker outputs... I rarely listen at ultra high db levels however it does crank up nicely when I do.
My room is about 24x20 carpeted, glass at the far end from the system with an 8' ceiling and is open to the kitchen in an L shape which is another 15x20 space. Far from an ideal listening room...
The Oly II's are 1 db less efficient that the III's and don't have the same bottom end response however they are amazing in many similar ways... I would have purchased OlyIII's if I could have found them used at the price you are pondering given that they may be in excellent condition with original boxes etc.
My suggestion to you is this... it's hard to go wrong either way and there is a bit if time pressure on the OlyIII's... I'd suggest you BUY THEM and if you get tired of them simply sell them... like rent, it might cost you a few hundred $$ over the course of a year or two to use while you may save up for whatever comes next... or like myself you may have no need to upgrade. Buy them and you get enriched with more listening experience...
I have found my audio "hobby" to be highly experiential even after working many years in the business myself... Those Oly's are a beautiful pair of speakers to live with and listen to. I think you will love them, of course keeping them long term will be up to you and yes they do need air around them, 2 feet in each direction of clear space is probably minimum but it is all unique to your own room for image and overall listening at their best as well as high grade cables, sources etc.
A friend was the rep for SF and ARC for years and she came by at some point and adjusted them in the room to her liking with instructions "Don't move them!" ... They have about 2' behind them and about 3' open to either side.
I have friends that LOVE the Prima Luna gear and I have had great experiences listening to the PL HP through SF $25K higher end speakers... great gear and amazing setup... I may swap some of that PL into my system at some point to see if I like it here..
Anyway, nothing ventured nothing gained... good luck and enjoy the music!