Been down that road the 2wq is nicer because of the q lets you taylor the bass to the room a little better. Now the question is do you need that. Unfortionally no one can answer that. If you find the bass is boomey (which is really hard for a sub that fast to do) get the q if you are satified wiht hte 2w just get another 2w and save the cash. I would also not sugest using a 2w and a 2wq they will just not match. If you are going to go for 2 2wq you may want to look into the quadros at that point.
Vandersteen Subwoofer decision
I know you are going to think this is yet another repeat of the question of whether the 2wq is that much better than the 2w, but this one is different. I own a 2w and I am looking to add second Vandy sub so I will have one for each of my front speakers. Seems to me like I would have three options: 1) buy another 2w for about $500, 2) buy a 2wq for about $800 used, or 3) sell the 2w and buy 2-2wq's for about a $1200 total investment. Anybody have an opinion? My first inclination is to just buy another 2w, as I don't see where my "Q" needs a lot of adjustment.