Ayre CX-5 / CX-7

 A friend loaned me his Ayre CX-5 CDP to listen to in my system.  I am impressed, however, when attempting to research this player, I’ve come across different versions of this CDP.  What I find is the CX-5, the CX-5xe, and the CX-5xemp.  The back plate of my friend’s player simply identifies it as “CX-5” (no ex, or exmp).  The only information i have found so far, is that the mp is a version upgrade that supposedly takes this unit, and upgrades it to a much higher level.  My questions are:

#1  Do I have these model designations correct (CX-5, CX-5ex, CX-5exmp)?

#2. What is the difference between these three (CX-5, CX-5ex, CX-5exmp)?

#3.  I may be looking to purchase one of these, how do I identify which one is which?

#4. Also, is there sonically much difference between the CX-5 and the CX-7?

In advance, thanks for your input!