One of the biggest problems with the X2 is the amount of backlash in all the axis. Instead of trying to lessen the backlash I simply installed digital scales with remote displays on the X and Y axis (Z is being installed this weekend) to act as a poor man'd DRO. Since they read the table's position directly, you can pretty much ignore the backlash present. The X scale is mounted on the back of the table with a protective aluminum shield over it. If you're using the tilting column then you'll lose Y travel unless you offset the scale's pickup to one side. I originally did that by extending the aluminum channel past the table and mounting the end of the scale in it.
However, that problem goes away with the solid column upgrade. The Y scale in mounted to the base on the left of the mill. The base's sides have a slight angle to them, but that doesn't matter when mounting the scale so long as it remains parallel to Y axis. I've found the table itself shields the scale sufficiently.
This is absolutely, positively the first upgrade which should be done to the mill. I don't really understand how someone can use an X2 without it.