Few questions on which speakers to get

Hi

Currently own a setup of Polk Audios for a 5.2 setup. While they generally have good effects for movies, I am not particularly happy with the center channel CsiA6 (dialog is often not too clear or not loud enough). Boosting the center channel level helps somewhat, but it also often tends to boost other sounds that I don't particularly like listening to at boosted levels.

I have also briefly heard the Sierra 1s a couple of years ago, and I was highly impressed by them for playing music, compared to my RtiA7s.

So the plan is to maybe slowly upgrade towards some Sierra setup, that will make listening to music a much more pleasurable experience and hopefully maybe provide a more clear dialog when movie watching. Not sure about the later .. but worth trying. I don't think it is going to be any worse anyway.

My room is about 17' x 20' x 8', and already have two DIY 18" subs in 4cf boxes.

I am planning to start with LCR of Sierra 2s, and later upgrade to some 5.2.4 or 7.2.4 setup. I was thinking to maybe just go with HTM200 for all surround, but am now contemplating to maybe save more, and for next step after the LCR purchase, to also get another pair of Sierra 2 for 5.2 surround setup (will allow me to listen to multichannel music with a complete Sierra 2 setup), and then after that, get some on-ceiling speakers for an Atmos setup. Those would probably be the HTM 200s.

This may take a couple of years to complete, but I think may be worthwhile pursuing.

Few questions I was hoping to get some input on

1. I have had a few recommendations for the Horizon if dialog clarity is very important.
Is Horizon that much better than S2 ?

This is one of my objectives, so wondering how much the Horizon will improve things over the S2 (Which I have not heard yet). I don't think I listen at loud volumes, I usually watch movies at ~-28dB to -32dB, and listen to music a little bit louder ..though probably not higher than -20dB.

Some concerns I have with the Horizon option are

- Mismatch with the S2 mains ( I tend to notice these things, I really did not like the transition from S1 to Polk surround when testing them with sound panning across)
- Price (I could get a pair of S2 for one Horizon, and budget is a bit of a concern)
- Space in cabinet, it is not going to fit, projector screen is low (and not AT), so finding a place for the Horizon will be tough .. (S2 will fit nice, though I may need to angle /tilt it a bit as it will likely be placed below L/R height.)

2. Would HTM-200 be a good surround complement for the S2 or should I consider something else?

Assuming I achieve having a 5 x S2 setup, in the future I was thinking to maybe invest in 4 x HTM 200 for a 5.2.4 Atmos setup.

Or maybe even 6 x HTM 200 for a 7.2.4. Alas that might leave me with 5 x S2 and 2 x HTM 200 in bed layer, but if I put the S2 pair for front wides, and HTM 200 for rear surround it might work well enough ?

3. Driving the S2. Will they sound much better with a dedicated amp, or is receiver enough ?

When I heard the S1 I used my current Pioneer SC-1227-K receiver that I still use, and they sounded really nice (obviously, because I am here now ..), not sure how it will work with the S2s though.

I will in the future upgrade to maybe one of the newer Denon's that will have Audyssey XT32, and at least 9 channels for an Atmos setup, but still not sure if even the Denon might work poorly compared to a dedicated Amp for music listening.

Honestly, I have been reading around already, and I think the answer to my questions (and for my situation) will likely be

1. Get the S2 for center too
2. HTM-200 will work fine
3. Receiver will do fine

But thought might as well get some more advice / input that can guide my plans.

Thanks !