Do you use a Subwoofer when listening to stereo?

I like functionality of avr where I can view tv screen while listening to stereo.

its very easy with the marantz avr.  I just press one key on remote to change source and that’s it ( ‘video select’ is their version of independent service).  Of course all this follows pressing play on roon.
not sure if other higher end preamps will work this well.

I use 4 subs in my main system.  I have 3 smaller systems.  Each of them has a subwoofer.  Where space permits, more is better.  

I have to agree with the person that said to consider ditching the receiver before you do anything else.  Get a preamp (or an integrated amp and ditch the Mac amps also) that has home theater bypass and use it for two channel listening and limit the Marantz to home theater use.  Then start adding some subs.

Why don’t you like McIntosh? Due to multi Chanel amp? Mac does a great job with amps under one roof.  That’s why the don’t sell smaller mono amps, the don’t need too.

i likely will get a stereo preamp and need to explore the process of switching back and forth between stereo and ht, ie. How many steps involved.

I'm an old school guy. I have a reasonably priced Paradigm 10" subwoofer parked to the left of my out-in-the-room NOLA Boxers, set up against the back wall but not too near the corner. I used my ears and a stereo test CD to match levels with the rest of my system and minimize boom. My system doesn't go all the way down to 20hz but I figure I'm able to enjoy a pretty good 30.  Bottom line (heh-heh) -- the subwoofer significantly enhances my modest system. Not only does it provide bass, it increases the size and believability of the soundstage.

i likely will get a stereo preamp and need to explore the process of switching back and forth between stereo and ht, ie. How many steps involved.

Not much to explore fortunately. If you get a preamp with a HT bypass feature you just push one button to switch between HT and stereo and that’s it, and when in stereo the Marantz is completely out of the signal path. I did this for years before I got a dedicated listening room and it works beautifully — best of both worlds really.

So, very quickly on how this works so you see how how absurdly simple this is — you just need one pair of interconnects and run them from the front L/R preamp outs from the Marantz into the HT bypass input on the stereo preamp and hook the line outs from the stereo preamp to the inputs on the Mac and you’re done. That’s it. Literally takes two minutes, and you won’t believe how much your 2-channel performance will improve — the preamp sections of most AVRs are just crap, relatively speaking.

BTW, this also works fine if the stereo pre doesn’t have a HT bypass and still involves the same hookup and pushing one button and adjusting volume on the pre to a predetermined level for watching movies/TV (can go into more detail if you might go this route) and that’s it. Start shopping for a good stereo preamp — it’ll be one of the most significant upgrades you’ll ever make. Hope this helps, and best of luck.