Hi dbt, I also have the X5's and they are very good sounding as many have said. Just curious what you preferred about the X4s? Obviously the electronics, DAC and room will be much different that what you have so that would influence the sound a lot. Clayton uses top notch equipment at his shows that he feels synergizes well with his speakers.
I'm not looking to change my X5s to get the X4s as that would most likely be more of a lateral type move and I use lower powered amplification so the X5 is a better fit for me.
Just curious what you felt sounded better as I'm sure he tweaked the crossover and the sound may be a little better. On a recent call I had with him he said both models sound virtually the same and it would be hard to really pick between them but I'm sure the X4 is a little better as those are the speakers he currently uses at shows.