I really doubt you are "limited" by your current set up in fact, I will guarantee it. Anything beyond what you have defines the law of diminishing returns and in your size room, it defines possibly more
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The SF Stradivarius are arguably one of the best speakers out there a statement product by a fine manufacture (and one of my favorites). If you cannot enjoy this set up...then, I hate to tell you this, but there is something seriously wrong with YOU. It is one thing to wish/want/envy a system upgrade when your budget constrains you, but clearly this is not the case with you. There are people that have been in the hobby for decades and will never ever experience the audio presentation in their home such as you have.
The only thing that I wish you could have experienced is the journey that most of us have gone through. Yes, you spent 2 years with clearly an unlimited budget. I, for one, started off with a $2K set up 15 years ago. Since that time I have lived with bad choices, wastes of money, incredible scores, giant killers and all of it leading to the place I am today. I have about a $45K (msrp) in my set up and it sounds pretty damn good. Better then most. (it is the system posted on this site, it has completely changed - I will update someday soon). It was this journey that has educated me and like all other aspects of my life, made me the audiophile/person I am today.
One of the hardest lessons learned and one I wished I learned years before I actually did is that to trust yourself and enjoy what sounds good to you...then run with it. Listen to yourself: You have $40K in speakers and you are wondering what you are missing by not spending $80K...Does that no sound odd to you?
Don't get me going on your 200SF listening room that houses this rig....
No offense intended...John