Responses from -cm-

Remarkably better sound possible with just 1 system component change?
What is your listening environment like? I know you said that treatments aren't feasible, what about arrangement?  
What about Uni Din?
I bought a SMARTractor recently also. I haven't begun exploring the various alignments yet myself, but I found this article interesting.https://www.analogplanet.com/content/uni-din-versus-l%C3%B6fgren-b-just-clarify 
Turntable belt replacement
I bought a replacement for my 7.3 not long ago from herehttps://hifiheaven.net/shop/Music-Hall-Genuine-OEM-Round-Turntable-Drive-Belt-for-MMF7-3-MMF9-3-Turn... 
The problem with Magicos
Do they come in blue? 
Audiophile metal albums
Volbeat - Seal the Deal and Let's Boogie is a good one. 
Semi-Compact Integrated Amp w/ Excellent Sound Quality?
You might find the Marantz HD-AMP1 is what you are looking for. I tried it and the matching CD player with a pair of Wharfedale 80th Dentons for the bedroom and ended up keeping the whole setup. I bought open box or refurb, so the price was even b... 
Your favorite 'concept' album
Jeff Wayne's Musical Version Of The War Of The Worlds 
SS Integrated amp w/front-mounted 1/8” mini-jack for personal media players ($1~3k range)
Music Hall a15.3 https://musichallaudio.com/product/music-hall-a15-3-integrated-amplifier/  
Help Upgrading My Phono Chain
If you want to stay in the Rega family, here's a link to a great deal.https://www.musicdirect.com/turntables/rega-rp8-turntable-no-cartridge-demo  
WAF --
lol thanks 
What Percentage Off Would You Expect to Discount For Open Box Amp with Blemish
Agree with @slaw  
Does altitude change the sound of speakers??
I moved from 800' to 7220' about a dozen years ago, and do not recall any significant change in speaker sound due to altitude. The ability to listen at volume levels that do a system justice was an improvement very much more readily noticeable.I... 
The System Percentages Thread
Interesting thread, thanks, OP. Interesting too, that I also am coming back into the hobby (disease?) after a long hiatus.I'll save the explanation and genesis of this system for another thread, but briefly, I wanted to see what sort of hifi syste...