The x version 1, which I have, are made to play very low freq. that some subs cannot reach in that area. Jacob has stated this some time ago. And yes, they don't play the higher notes very well. It's been said time and time again. You might find someone or 2 that didn't like the sound of this sub.
The x version 2 takes it to another level and less "mega surround" the version one has. This sub should play all freq that your after, in a good designed enclosure.
The W7 is a good sub, but imo and many others, it's way over priced. Even seen some on CL and such still wanting top dollar for a used sub. Funny how the W7's have been out how many years now, and not once have they dropped in price.
If it were me, I'd get the xv.2 You can always change them out later if you don't like them. Got some help here to get you up and running such as a box design, and such.