Tommy
The X250.8 has better control of the bass, and is more dynamic with better imaging then the X250.5. The X250.5 has a more liquid mid-range and tube like sound. Overall I prefer the X250.8, but both worked very well with my Sasha's. If you have a very damped listening room the X250.8 would be the better choose as the X250.5 bass is deep but is not as well controlled and can sound a bit soft.
Wilson recommends toeing-in the speakers it provides better imaging and resolution in the mid and upper ranges. You toe them in to you ideal listening position and with the Alexia's you can adjust the tweeter and mid-range to your listening height which makes a difference.
