Choosing Sub-woofers. Please advise ASAP.

" Your speakers are pretty full range so you'll need 12 inch or larger to extend lower if needed at all.  Two are better than one for balance across the room. "

" @ mapman. I thought so too. That is my original idea but shaken up a little when spoke to the dealer. He suggested his 2 used 10" subs at super crazy discount....

Also the room size is OK for 2x 12" subs?"

Not true. If you buy subs with 12in drivers, the only thing you can be sure of is that your subs will have 12 in drivers. Are all 12in drivers identical? Better yet, if you have one of the drivers blow in your Wilson's, are you going to run down to your local Radio Shack for replacement? People may disagree with me on this, but I think the quality of the speaker is a factor in how it sounds. 

If you want to make bass, you can either move a large driver slow or a small driver fast. If all other factors are equal, there'a no difference. Not only that, a high quality 8 or 10 in woofer, can easily outperform a low quality 12 in unit. 

" If you want to make bass, you can either move a large driver slow or a small driver fast. If all other factors are equal, there'a no difference. "

" That doesn't make any sense. A driver's movement corresponds to the frequency it's asked to reproduce. If it's a pure 32 Hz tone, the cone will move at 32 cycles per second, regardless of the cone's diameter. "

That's not true. The lower the frequency, the more air you need to move. If you make an 8in speaker move the same amount of air as a 10in speaker, then you get the same frequency. That means the 8in speaker has to move faster than the 10in speaker. 

Check the specs on some speakers. Quite often you'll see speakers with smaller drivers that can go just as low as speakers using larger drivers. A good starting point would be to have a look at Carvers Sunfire Sub. He does a way better job of explaining this than I do.

http://www.sunfire.com/whitepapers/Sunfire_Subwoofer_Whitepaper.pdf
"

" Now, nothing related to sub but anyone know good decent Flat cable for my surround pair where I need to hide under the rug."

Not a good idea. Use a real pair of speaker cables. You don't have to go with anything really expensive, but you don't want to run cheap install cable to a $12,000 pair of Wilson's. Get something higher quality that matches the front speakers (It doesn't have to be exactly the same, just go down 2-3 steps in the same brand). As far as running it goes, figure something out. Maybe run the cables down the side walls and cover it with molding.

When I redo my listening room, I'm going to install the molding with a gap in it large enough to fit cables. Then all I have to do is run a wire snake through the gap and pull the wires through. For high speakers (Atmos), you can do the same thing with crown molding.