Posting a picture of the midrange speakers which come stock on the X3. Notice the magnet... Yes, that's actually a magnet...
So, you'll notice that the spacer/mount of the speakers are a bit thick (about 1/2"). What this gave us was a working space to replace that with a board.
We screwed the Focals, with 4 mounts, on the board, and then drilled 3 holes in the board to mount/screw the Focals on the stock speaker door mounts.