As far as I can tell, the DXx and the EXx are electrically and mechanically identical. The only difference is that the EXx has a die-cast basket on the back of the driver. It completely covers the back of the cone and has a bunch of 1/2"-3/4" holes in the perimeter. There is a layer of air-conditional filter foam on the inside of the basket. The basket is glued on with silicon sealant and is easily removed, although this voids your warranty. When you remove the EX basket, you will find a normal DX frame, complete with binding posts. The only thing that you will be missing is a cosmetic cover for the magnet. You will also be surprised at how ridiculously small a neodymium magnet is compared to a ceramic magnet.The theory is that the EX basket reduces reflections from the rear of the speaker cabinet from getting back into the cone. Maybe so. Perhaps this is effective in horn cabinets. However, when using an EX in a resonant cabinet, I find that the basket prevents the driver from loading the cabinet properly. A DX driver works much better in a resonant cabinet, and you save $150 to boot.
Bob