Personally, I would go for the Arc first.

That was the opposite of what i was leaning towards….cause even the 300’s are “new” it’s not so common to get a discount on these.

The ARC is vey popular and the price for a used secoundhand ARC is just on average $150 to $200 less than new….in otherwords very expencive. So for me is no use in buy secoundhand.

I was talking about the improvement in sound quality rather than available discounts.

I’d go with the Arc first as you can use that for music and your TV.

Add the two 300s for the rear surrounds as a second step or after listening consider a Sub or mini-Sub as the second option.

Then either the Sub or surround 300s, whichever you didn’t already get.

Last the additional 300s for your stereo pair as they won’t improve your TV sound, or maybe consider a pair of Fives instead?

Like i said…for me is the expencives are a big deal of “investments” in Sonos. So i’m allways looking for good deals. The Arc have been on the market for some years now,so it’s more common to see dicount to the Arc than the 300’’s.

But on the other hand….if i go for the Arc,i can use the Beam on another system(i got tree TV-sets,in progress for expands. I allready got the Subs&surrounds where the Arc will be,but i really like to switch out my Era 100’’s for the 300’s in the back….future plans is a secound 300-pair(with sub) grouped up front(like Daniel does on his Youtube-ch “Never Enough Tech”.

The only thing worries me bout the 300’s are….i need to put them on a wall-bracket (the Org “L-shaped" once) but i’m afraid if these 300’s are not easy to place in a room. And when i drilled wholes in the wall,ther’s no turning back…..i got a brand new house,snd start build hifi for the future could be a little scary when you start leave marks(or other evidence) of hifi around the house.

You do know Sonos does not provide for any Sonos speaker to be used as “fronts” in a home cinema set up?

#106rallye….yes…i can’t add anything “more” in my cinema-home theater set with the Beam. But i can add a stereopair(perhaps with sub) of 300’s(makes more sense with the “spacial audio” offerd in the 300’s makes them the best alternative in home cinema?) The 300’s up front are grouped with the Home cinema i belive thats how it’s done. 

For my understanding the “joined” stereopair of 300’s will allso play the quality the Cinema-setup is playing.

And i have figure it out that i pretty much need the ARC to let the 300’s shine their glory. 
But i could be moving out on thin ice now with my understanding of Sonos-systems and speakers,so…..

And my home cinema i must admidt….the space is not big and i got a challange with layout of the room. I got multiple angles on the sealing and they got deep windows.
 

When you group speakers there's a delay of 75ms on the grouped speakers with TV sound. Since the speakers are not part of the surround “room” they will also not ad anything to a spatial set up (just play along in stereo).

Since you also mention financial constraints I'd go for the Arc with Era 300's for surrounds.

….oh,there’s gonna be a delay? I have not heard the ones that have Youtube-channels covering this set-up. I was curious and i was trying out different speakers including my two Bookshielfspeakers witch i placed up front as i was planning on use the 300’s instead. I did not notice any delay but it might make a bigger difference with the 300’s(?)

But i did not liked the sound including the Bookshielf’s so i skipped them. Now i just use ERA 100’s. They are ok,but i’m not happy with the “surround-impression” yet. 

There is always a delay between a Sonos Home Theater room and any grouped rooms. 75ms is the minimum, but depending on the settings, it can be more.

When playing music, all rooms in a Group are time aligned. If you include a TV room, there is a time offset between the TV audio and other members of the Group. You can fuss with the TV lip sync and possibly improve the overall situation, but this is not guaranteed.

#buzz….I did not know that. But thanx for uplight me. I’m not trying to be a smartaxx or a betterknower. I have been spending quite bit of time watch Youtube collect som info on Sonos and it’s network/communety/products. But al in all comes down to me/us as a consumer and our experience beyond 3-4yo Youtube-videos. I have just bought my first Sonos two months ago,so all in all i’m a newbe. I have been into soundsystems in cars(from late 80’s untill few years ago….) but not like a pro. I did use fiberglass when intalling aquipment in my cars,so that makes me over average.

So what i’m saying that i do “know sound” to a certain level.But never inside a home,untill now
 

It’s a different ‘world’ in those tiny little automotive rooms compared to a house. Sound is an ornery creature to deal with — even in the tiniest rooms. Speakers interact with the room and you can have wildly different responses with different speaker and listener locations.

Be careful with those YouTube “experts”. “X” is an unknown and a “spurt” is a drip under pressure.