I agree, it's nice to see the rigs of the people we talk to so much. I tried to stir up interest in it for quite a while, hard to get some folks to go along. Look at the date of my OP, just a few weeks after Amir started the site. LOL
I've got new speakers coming and have made a few changes since that last photo was put up. I'll update it for sure after I get the new speakers, they're a surprise for all but a couple here. LOL
I love my Marantz 7703, it sounds beautiful with the best material, if I do say so myself. Before that I had a 7701 which I sold to Blumline 88 and he measured & reviewed here. He still uses it for his HT AFAIK. I only sold it cause I wanted to get into Atmos & DTS-X immersive stuff.
https://www.audiosciencereview.com/forum/index.php?threads/marantz-avr-7701-dac-measurements.3485/
I wouldn't take much to heart from the reviews. Amir is a tech head and is never happy unless a unit measures perfectly, but I highly doubt that any of the measured weaknesses are actually audible. All loudspeakers distortion & other problems are orders of magnitude worse than the pre-pro and hearing them above the speakers problems is highly doubtful. Beyond that you'll have Audyssey room correction and when combined with the Editor app will allow you to do a damn good job DRC
How well versed are you with the Marantz?
After a number of years with the two units I believe I'm fairly well versed. I believe your asking if the 7703 can hold two different configuations internally so you can just switch back and forth, sorry no, it's not that easy. You could store 2 or more completely different system config's on thumb drives as "backups" and switch between them that way but it's not instant. It takes a while to do, maybe 5 minutes total?
Can't wait to get the new speakers installed