Aham,
If you want to get the most out of your money, I would suggest staying away from the in-wall series, and getting normal M22s with a mounting bracket ($40 more). This will save you money and you will get the same sound for less.
You're going to want to save as much money as possible if you want to get a good theatre sound in a room that big, you'll at least need an EP350v3 from Axiom.
I would suggest the following for your room and your $2000 budget (All from the
Factory Outlet):
2 x M22s for your mains: $424 USD
1 x VP150 for your centre: $367 USD
2 x QS8s for your surrounds: $486 USD
1 x EP350v3 for your sub: $682 USD
3 x Axiom FMB for your 22s and 150: $120 USD
Your grand total before the 5% shipping discount is $2079 USD. After the 5% shipping discount you're sitting at a pretty
$1975 USD. You have better surrounds and a better sub for your LFE.
This is the best way to spend your money IMHO, you get the QS8s for your bigger room, and the EP350v3 for your bigger room.
Alternative option for your centre channel:
If you would like another option for your centre channel you can go the route of 2 bookshelf M2s above and below your screen, this will also be cheaper than the VP150 by about $100 USD I think.
This is the setup that I have at my theatre and I love it:
With a 108" screen, I am not sure you'll have the room. I have a 92" screen and 7'9" ceiling height.
Edit again: Have you factored in all of your cables that you will need into your final price? I would suggest monoprice.com for all your video cable needs (HDMI and component runs to your projector) and bluejeanscable.com for your in-wall 12 guage speaker wire.
If you need help with planning out your wiring, just give me a pm.
