The SuperSats are not designed for the baffle to be flush to the wall, they are designed for on wall mounting or stand/shelf mounting. If you really want flush, get the MPX as you originally planned. If you want to know how they sound, check out the press from the CEDIA 2016 trade show. (Here's one link: www.avsforum.com/goldenear-supersub-x-an...tem-at-cedia-2016-2/, I'm sure a quick search will yeild a few mroe.)

Two quick questions then.
1. I plan to put the supersats in a 3" deep by 15" wide recess, so they will be pretty wide open to disperse sound into the rooms. Will that help with this issue or still recommend surface mount or going with MPXs?
2. My concern with MPX is my friends experience with hearing the MPX and then replacing with SuperSat to a noticeable difference. So given the choice of MPX vs SuperSat, what is going to give us the best sound quality?

1. Sure, that's fine. I thought you meant flush to the speakers' baffle.

2. Well, my experience is they sound very similar when properly setup. The MPX will play lower (allows for a lower crossover), but, in-walls still have to deal with the wall itself (and the infinite baffle it represents), which are variables that are not present in the SuperSat.

I think most fans of high-quality audio playback will tell you floorstanding (or stand-mount) is best, on-wall if you can't, in-wall if you must. (I am NOT suggesting in-wall systems can't sound great, the CEDIA report makes that pretty clear.)

So we are all set. Picked everything up today from the dealer.
Another question that I couldn't find guidance on here for and found nixed opinions on other forums.
Should I consider a baffle of some type to protect the in ceiling speakers from dirt and debris above ceiling? I installed Ruxol insulation and it has a lot of little mineral rocks that I fear may damage or cause issue with the speakers.
Was thinking of something like these.
Amazon Speaker Baffles

They are a little tight to the speaker. Maybe just some heavy mil plastic spread out over the top would work too?

Thanks!

Not necessary, just toss a piece of roll insulation over the speaker, as the manual suggests.