Has anyone taken apart these things before? My theory always is...if someone put them together, they can come apart...right? But I don't like to be the first one to experiment! 
UPDATE:
I was able to get them apart and get my embroidery done! They turned out great! I was a little apprehensive, but dove in and it actually was not that hard.
Instructions:
1. To get the headrest off, pull the back seat cover off by pulling the tabs out at the bottom of the cover and pulling down to release the clips at the top.
2. You will see the yellow plug that the headrests plug in to at the top, unplug.
3. You will need a small allen wrench to push into the small hole on the left post (looking at it from the back) and depress the button on the right post at the same time and the headrest will slide up and out.
4. Remove the back plastic cover by using a pry tool to pop it off.
5. The material is clipped to this cover with 6 clips, four on the bottom and 1 on each side. Simply use a pry tool and straight head screwdriver to pop the clips up and pull the material out.
6. Once those clips are released the cover will slide off and down the posts.
7. The rest of the cover is held on to the headrest with the same type of clips as where on the cover. There are 3 along the top, 3 along the bottom and 2 on each side.
8. Use a pry tool and straight head screwdriver to pop the clips up and pull the material out.
9. Once all the clips are released, work the cover off by pushing the pad and pulling the cover off from the corners. Once the cover is clear, the headrest assembly will actually separate from the pad.
10. To put the cover back on, simply do the reverse of the steps above.
UPDATE:
I was able to get them apart and get my embroidery done! They turned out great! I was a little apprehensive, but dove in and it actually was not that hard.
Instructions:
1. To get the headrest off, pull the back seat cover off by pulling the tabs out at the bottom of the cover and pulling down to release the clips at the top.
2. You will see the yellow plug that the headrests plug in to at the top, unplug.
3. You will need a small allen wrench to push into the small hole on the left post (looking at it from the back) and depress the button on the right post at the same time and the headrest will slide up and out.
4. Remove the back plastic cover by using a pry tool to pop it off.
5. The material is clipped to this cover with 6 clips, four on the bottom and 1 on each side. Simply use a pry tool and straight head screwdriver to pop the clips up and pull the material out.
6. Once those clips are released the cover will slide off and down the posts.
7. The rest of the cover is held on to the headrest with the same type of clips as where on the cover. There are 3 along the top, 3 along the bottom and 2 on each side.
8. Use a pry tool and straight head screwdriver to pop the clips up and pull the material out.
9. Once all the clips are released, work the cover off by pushing the pad and pulling the cover off from the corners. Once the cover is clear, the headrest assembly will actually separate from the pad.
10. To put the cover back on, simply do the reverse of the steps above.
