Wilson Alexandria X2 vs Alexx

Having heard both, I would easily go with the Alexx. The old X2 utilizes the bright, ringing and nasty ( IMO) Focal titanium dome. That alone would discount this speaker for me. You have enough power to drive either speaker. 
The price of the old Alex 2 is still quite high for what it is, IMO, BUT the Alexx is a lot more pricey ( as it should be).

I lived with the X2 for some time and, while I loved them*, I would unreservedly recommend you go for the Alexx. To me, they sounded faster, more open, and more dynamic than my X2s—more modern if you will. They do seem more difficult to set up and much more difficult to drive, but your amplification should be more than enough to make them rock.

*The A’s would disappear in my average-sized room (I mean sonically, of course) and provide beautiful unrestrained sound — but I think the new ones sound even better.