As long as it does not impead the cone movement of the 6.5, I dont think you'll hear a difference. I actually think it wil be better. Old rule of thumb is to keep the mid and tweet 6" from each center for best alignment.
I have my Q's setup just like TonyD has his, this pulls the image up and toward the listening position. Its a good route to go if you dont want to do kick panels, although with kick panels wiring is sooooooo much easier
